Prediction of therapy response of breast cancer patients with machine learning based on clinical data and imaging data derived from breast [18F]FDG-PET/MRI

PURPOSE

To evaluate if a machine learning prediction model based on clinical and easily assessable imaging features derived from baseline breast [18F]FDG-PET/MRI staging can predict pathologic complete response (pCR) in patients with newly diagnosed breast cancer prior to neoadjuvant system therapy (NAST).

METHODS

Altogether 143 women with newly diagnosed breast cancer (54 ± 12 years) were retrospectively enrolled. All women underwent a breast [18F]FDG-PET/MRI, a histopathological workup of their breast cancer lesions and evaluation of clinical data. Fifty-six features derived from positron emission tomography (PET), magnetic resonance imaging (MRI), sociodemographic / anthropometric, histopathologic as well as clinical data were generated and used as input for an extreme Gradient Boosting model (XGBoost) to predict pCR. The model was evaluated in a five-fold nested-cross-validation incorporating independent hyper-parameter tuning within the inner loops to reduce the risk of overoptimistic estimations. Diagnostic model-performance was assessed by determining the area under the curve of the receiver operating characteristics curve (ROC-AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. Furthermore, feature importances of the XGBoost model were evaluated to assess which features contributed most to distinguish between pCR and non-pCR.

RESULTS

Nested-cross-validation yielded a mean ROC-AUC of 80.4 ± 6.0% for prediction of pCR. Mean sensitivity, specificity, PPV, and NPV of 54.5 ± 21.3%, 83.6 ± 4.2%, 63.6 ± 8.5%, and 77.6 ± 8.1% could be achieved. Histopathological data were the most important features for classification of the XGBoost model followed by PET, MRI, and sociodemographic/anthropometric features.

CONCLUSION

The evaluated multi-source XGBoost model shows promising results for reliably predicting pathological complete response in breast cancer patients prior to NAST. However, yielded performance is yet insufficient to be implemented in the clinical decision-making process.

High serum levels of leucine-rich α-2 glycoprotein 1 (LRG-1) are associated with poor survival in patients with early breast cancer

BACKGROUND

Leucine-rich α-2 glycoprotein 1 (LRG-1) is a secreted glycoprotein that is mainly produced in the liver. Elevated levels of LRG-1 are found in a multitude of pathological conditions including eye diseases, diabetes, infections, autoimmune diseases, and cancer. In patients with early breast cancer (BC), high intratumoral LRG-1 protein expression levels are associated with reduced survival. In this study, we assessed serum levels of LRG-1 in patients with early BC and investigated its correlation with the presence of disseminated tumor cells (DTCs) in the bone marrow and survival outcomes.

METHODS

Serum LRG-1 levels of 509 BC patients were determined using ELISA and DTCs were assessed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. We stratified LRG-1 levels according to selected clinical parameters. Using the log-rank (Mantel-Cox) test and multivariate Cox regression analysis, Kaplan-Meier survival curves and prognostic relevance were assessed.

RESULTS

Mean serum levels of LRG-1 were 29.70 ± 8.67 µg/ml. Age was positively correlated with LRG-1 expression (r = 0.19; p < 0.0001) and significantly higher LRG-1 levels were found in patients over 60 years compared to younger ones (30.49 ± 8.63 µg/ml vs. 28.85 ± 8.63 µg/ml; p = 0.011) and in postmenopausal patients compared to premenopausal patients (30.15 ± 8.34 µg/ml vs. 26.936.94 µg/ml; p = 0.002). Patients with no DTCs showed significantly elevated LRG-1 levels compared to the DTC-positive group (30.51 ± 8.69 µg/ml vs. 28.51 ± 8.54 µg/ml; p = 0.004). Overall and BC-specific survival was significantly lower in patients with high serum LRG-1 levels (above a cut-off of 33.63 µg/ml) compared to patients with lower LRG-1 levels during a mean follow-up of 8.5 years (24.8% vs. 11.1% BC-specific death; p = 0.0003; odds ratio 2.63, 95%CI: 1.56-4.36). Multivariate analyses revealed that LRG-1 is an independent prognostic marker for BC-specific survival (p = 0.001; hazard ratio 2.61).

CONCLUSIONS

This study highlights the potential of LRG-1 as an independent prognostic biomarker in patients with early BC.

Towards a fast PET/MRI protocol for breast cancer imaging: maintaining diagnostic confidence while reducing PET and MRI acquisition times

OBJECTIVES

To investigate the diagnostic feasibility of a shortened breast PET/MRI protocol in breast cancer patients.

METHODS

Altogether 90 women with newly diagnosed T1tumor-staged (T1ts) and T2tumor-staged (T2ts) breast cancer were included in this retrospective study. All underwent a dedicated comprehensive breast [18F]FDG-PET/MRI. List-mode PET data were retrospectively reconstructed with 20, 15, 10, and 5 min for each patient to simulate the effect of reduced PET acquisition times. The SUVmax/mean of all malign breast lesions was measured. Furthermore, breast PET data reconstructions were analyzed regarding image quality, lesion detectability, signal-to-noise ratio (SNR), and image noise (IN). The simultaneously acquired comprehensive MRI protocol was then shortened by retrospectively removing sequences from the protocol. Differences in malignant breast lesion detectability between the original and the fast breast MRI protocol were evaluated lesion-based. The 20-min PET reconstructions and the original MRI protocol served as reference.

RESULTS

In all PET reconstructions, 127 congruent breast lesions could be detected. Group comparison and T1ts vs. T2ts subgroup comparison revealed no significant difference of subjective image quality between 20, 15, 10, and 5 min acquisition times. SNR of qualitative image evaluation revealed no significant difference between different PET acquisition times. A slight but significant increase of IN with decreasing PET acquisition times could be detected. Lesion SUVmax group comparison between all PET acquisition times revealed no significant differences. Lesion-based evaluation revealed no significant difference in breast lesion detectability between original and fast breast MRI protocols.

CONCLUSIONS

Breast [18F]FDG-PET/MRI protocols can be shortened from 20 to below 10 min without losing essential diagnostic information.

KEY POINTS

• A highly accurate breast cancer evaluation is possible by the shortened breast [18F]FDG-PET/MRI examination protocol. • Significant time saving at breast [18F]FDG-PET/MRI protocol could increase patient satisfaction and patient throughput for breast cancer patients at PET/MRI.

Conventional Imaging, MRI and 18F-FDG PET/MRI for N and M Staging in Patients with Newly Diagnosed Breast Cancer

Background: This study compares the diagnostic potential of conventional staging (computed tomography (CT), axillary sonography and bone scintigraphy), whole-body magnetic resonance imaging (MRI) and whole-body ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET/)MRI for N and M staging in newly diagnosed breast cancer. Methods: A total of 208 patients with newly diagnosed breast cancer were prospectively included in this study and underwent contrast-enhanced thoracoabdominal CT, bone scintigraphy and axillary sonography as well as contrast-enhanced whole-body ¹⁸F-FDG PET/MRI. The datasets were analyzed with respect to lesion localization and characterization. Histopathology and follow-up imaging served as the reference standard. A McNemar test was used to compare the diagnostic performance of conventional staging, MRI and ¹⁸F-FDG PET/MRI and a Wilcoxon test was used to compare differences in true positive findings for nodal staging. Results: Conventional staging determined the N stage with a sensitivity of 80.9%, a specificity of 99.2%, a PPV (positive predictive value) of 98.6% and a NPV (negative predictive value) of 87.4%. The corresponding results for MRI were 79.6%, 100%, 100% and 87.0%, and were 86.5%, 94.1%, 91.7% and 90.3% for ¹⁸F-FDG PET/MRI. ¹⁸F-FDG PET/MRI was significantly more sensitive in determining malignant lymph nodes than conventional imaging and MRI (p < 0.0001 and p = 0.0005). Furthermore, ¹⁸F-FDG PET/MRI accurately estimated the clinical lymph node stage in significantly more cases than conventional imaging and MRI (each p < 0.05). Sensitivity, specificity, PPV and NPV for the M stage in conventional staging were 83.3%, 98.5%, 76.9% and 98.9%, respectively. The corresponding results for both MRI and ¹⁸F-FDG PET/MRI were 100.0%, 98.5%, 80.0% and 100.0%. No significant differences between the imaging modalities were seen for the staging of distant metastases. Conclusions:¹⁸F-FDG PET/MRI detects lymph node metastases in significantly more patients and estimates clinical lymph node stage more accurately than conventional imaging and MRI. No significant differences were found between imaging modalities with respect to the detection of distant metastases.

Elevated sHLA-G plasma levels post chemotherapy combined with ILT-2 rs10416697C allele status of the sHLA-G-related receptor predict poorest disease outcome in early triple-negative breast cancer patients

Introduction

Triple negative breast cancer (TNBC) shows an aggressive growing and spreading behavior and has limited treatment options, often leading to inferior disease outcome. Therefore, surrogate markers are urgently needed to identify patients at high risk of recurrence and more importantly, to identify additional therapeutic targets enabling further treatment options. Based on the key role of the non-classical human leukocyte antigen G (HLA-G) and its related receptor immunoglobulin-like transcript receptor-2 (ILT-2) in immune evasion mechanisms of tumors, members of this ligand-receptor axis appear to be promising tool for both, defining risk groups and potential therapeutic targets.

Materials and methods

To follow this, sHLA-G levels before and after chemotherapy (CT), HLA-G 3' UTR haplotypes, and allele variations rs10416697 at the distal gene promoter region of ILT-2 were defined in healthy female controls and early TNBC patients. The results obtained were associated with clinical status, presence of circulating tumor cell (CTC) subtypes, and disease outcome of patients in terms of progression-free or overall survival.

Results

sHLA-G plasma levels were increased in TNBC patients post-CT compared to levels of patients pre-CT or controls. High post-CT sHLA-G levels were associated with the development of distant metastases, the presence of ERCC1 or PIK3CA-CTC subtypes post-CT, and poorer disease outcome in uni- or multivariate analysis. HLA-G 3' UTR genotypes did not influence disease outcome but ILT-2 rs10416697C allele was associated with AURKA-positive CTC and with adverse disease outcome by uni- and multivariate analysis. The prognostic value of the combined risk factors (high sHLA-G levels post-CT and ILT-2 rs10416697C allele carrier status) was an even better independent indicator for disease outcome in TNBC than the lymph nodal status pre-CT. This combination allowed the identification of patients with high risk of early progression/death with positive nodal status pre-CT or with non-pathological complete therapy response.

Conclusion

The results of this study highlight for the first time that the combination of high levels of sHLA-G post-CT with ILT-2 rs10416697C allele receptor status is a promising tool for the risk assessment of TNBC patients and support the concept to use HLA-G/ILT-2 ligand-receptor axis as therapeutic targets.

Correlation between Imaging Markers Derived from PET/MRI and Invasive Acquired Biomarkers in Newly Diagnosed Breast Cancer

PURPOSE

Evaluate the diagnostic potential of [¹⁸F]FDG-PET/MRI data compared with invasive acquired biomarkers in newly diagnosed early breast cancer (BC).

METHODS

Altogether 169 women with newly diagnosed BC were included. All underwent a breast- and whole-body [¹⁸F]FDG-PET/MRI for initial staging. A tumor-adapted volume of interest was placed in the primaries and defined bone regions on each standard uptake value (SUV)/apparent diffusion coefficient (ADC) dataset. Immunohistochemical markers, molecular subtype, tumor grading, and disseminated tumor cells (DTCs) of each patient were assessed after ultrasound-guided biopsy of the primaries and bone marrow (BM) aspiration. Correlation analysis and group comparisons were assessed.

RESULTS

A significant inverse correlation of estrogen-receptor (ER) expression and progesterone-receptor (PR) expression towards SUV_max was found (ER: r = 0.27, p < 0.01; PR: r = 0.19, p < 0.05). HER2-receptor expression showed no significant correlation towards SUV and ADC values. A significant positive correlation between Ki67 and SUVmax and SUV_mean (r = 0.42 p < 0.01; r = 0.19 p < 0.05) was shown. Tumor grading significantly correlated with SUV_max and SUV_mean (ρ = 0.36 and ρ = 0.39, both p's < 0.01). There were no group differences between SUV/ADC values of DTC-positive/-negative patients.

CONCLUSIONS

[¹⁸F]FDG-PET/MRI may give a first impression of BC-receptor status and BC-tumor biology during initial staging by measuring glucose metabolism but cannot distinguish between DTC-positive/-negative patients and replace biopsy.

Programmed death receptor ligand-2 (PD-L2) bearing extracellular vesicles as a new biomarker to identify early triple-negative breast cancer patients at high risk for relapse

PURPOSE

Based on the tumor-promoting features of extracellular vesicles (EV) and PD-L1/2-bearing EV subpopulations (PD-L1/2_EV), we evaluated their potential as surrogate markers for disease progression or eligibility criteria for PD-1 immune checkpoint inhibition (ICI) approaches in early triple-negative breast cancer (TNBC).

METHODS

After enrichment of EV from plasma samples of 56 patients before and 50 after chemotherapy (CT), we determined levels of EV particle number and PD-L1/2_EV by nanoparticle tracking analysis or ELISA and associated the results with clinical status/outcome and the presence of distinct circulating tumor cells (CTC) subpopulations.

RESULTS

Compared to healthy controls, patients had a tenfold higher EV concentration and significantly elevated PD L2_EV but not PD L1_EV levels. The most important clinical implications were found for PD-L2_EV. High PD-L2_EV levels were associated with a significantly reduced 3-year progression-free and overall survival (PFS and OS). A loss of PD-L2_EV after CT was significantly more prominent in patients achieving pathological complete response (pCR). Increased pre-CT PD-L2_EV levels were found in patients having NOTCH1-positive or ERBB3-positive CTC. The presence of ERBB3-positive CTC combined with high pre-CT PD-L2_EV resulted in a shorter PFS.

CONCLUSION

This study highlights PD L2_EV as a promising biomarker for risk assessment of TNBC patients and represents the basic for additional studies introducing PD-L2_EV as an eligibility criterion for PD-1 ICI approaches.

Clinical Decision Support for Axillary Lymph Node Staging in Newly Diagnosed Breast Cancer Patients Based on 18F-FDG PET/MRI and Machine Learning

In addition to its high prognostic value, the involvement of axillary lymph nodes in breast cancer patients also plays an important role in therapy planning. Therefore, an imaging modality that can determine nodal status with high accuracy in patients with primary breast cancer is desirable. Our purpose was to investigate whether, in newly diagnosed breast cancer patients, machine-learning prediction models based on simple assessable imaging features on MRI or PET/MRI are able to determine nodal status with performance comparable to that of experienced radiologists; whether such models can be adjusted to achieve low rates of false-negatives such that invasive procedures might potentially be omitted; and whether a clinical framework for decision support based on simple imaging features can be derived from these models. Methods: Between August 2017 and September 2020, 303 participants from 3 centers prospectively underwent dedicated whole-body ¹⁸F-FDG PET/MRI. Imaging datasets were evaluated for axillary lymph node metastases based on morphologic and metabolic features. Predictive models were developed for MRI and PET/MRI separately using random forest classifiers on data from 2 centers and were tested on data from the third center. Results: The diagnostic accuracy for MRI features was 87.5% both for radiologists and for the machine-learning algorithm. For PET/MRI, the diagnostic accuracy was 89.3% for the radiologists and 91.2% for the machine-learning algorithm, with no significant differences in diagnostic performance between radiologists and the machine-learning algorithm for MRI (P = 0.671) or PET/MRI (P = 0.683). The most important lymph node feature was tracer uptake, followed by lymph node size. With an adjusted threshold, a sensitivity of 96.2% was achieved by the random forest classifier, whereas specificity, positive predictive value, negative predictive value, and accuracy were 68.2%, 78.1%, 93.8%, and 83.3%, respectively. A decision tree based on 3 simple imaging features could be established for MRI and PET/MRI. Conclusion: Applying a high-sensitivity threshold to the random forest results might potentially avoid invasive procedures such as sentinel lymph node biopsy in 68.2% of the patients.

The Role of C-Reactive Protein as a Prognostic Biomarker in Patients with Early Breast Cancer Treated with Neoadjuvant Chemotherapy

Background

C-reactive protein (CRP) is an acute phase reactant influenced by inflammation and tissue damage. Elevated CRP levels have been associated with poor outcome of various cancers including breast cancer. However, evidence regarding a potential impact of CRP levels on outcome of neoadjuvant chemotherapy (NACT) in patients with early breast cancer (EBC) is insufficient.

Methods

Patients who had received NACT for EBC and had available data regarding CRP levels before therapy, pathologic complete remission (pCR), and follow-up were included. The association between CRP at baseline and outcome parameters was analyzed.

Results

152 women were included in this analysis; median follow-up was 5.8 years. No association between CRP at baseline and pCR rates could be detected. 6.6% of the patients developed a local recurrence, 10.5% developed a distant recurrence, and 5.2% died from breast cancer. A negative correlation (Spearman-Rho) between CRP at baseline and overall survival (OS) (correlation coefficient (CC) -0.255; p = 0.45), disease-free survival (DFS) (CC -0.348; p = 0.075), local recurrence-free survival (LRFS) (CC -0.245; p = 0.327), and distant DFS (DDFS) (CC -0.422; p = 0.057) was not statistically significant, although especially in DFS and DDFS a strong trend was detected. The probability of death from breast cancer was 2% if the CRP was <0.08 mg/dL and 40% if the CRP was >2.08 mg/dL; this association was highly statistically significant (χ²; p < 0.001). These results were independent from age, estrogen and progesterone receptor status, HER2 status, nodal status, and grading. The hazard ratio for OS was 5.75 (p = 0.004) for CRP <0.08 mg/dL versus CRP >2.08 mg/dL.

Discussion/Conclusion

CRP at baseline is not predictive for pCR in EBC after NACT in our patient dataset. However, an association of parameters of long-term prognosis with CRP could be demonstrated. Although the correlations of higher CRP levels at baseline and shorter OS, DFS, LRFS, and DDFS were not significant, a strong trend could be detected that was reproduced in the analysis of different groups of CRP levels and the probability of breast cancer mortality. Higher CRP levels are indicating a worse prognosis in EBC after NACT in this retrospective analysis. These results justify further investigation of CRP not as a predictive parameter for pCR but as a biomarker of long-term prognosis in EBC in prospective trials and may lead to therapeutic approaches with the aim of lowering CRP levels.

Lung Nodules Missed in Initial Staging of Breast Cancer Patients in PET/MRI-Clinically Relevant?

Simple Summary

Image-based primary staging in women with newly-diagnosed breast cancer is important to exclude distant metastases, which affect up to 10% of women. The increasing implementation of [¹⁸F]FDG-PET/MRI as a radiation-saving primary staging tool bears the risk of missing lung nodules. Thus, chest CT serves as the diagnostic of choice for the detection and classification of pulmonary nodules. The aim of this study was the evaluation of the clinical relevance of missed lung nodules at initial staging of breast cancer patients in [¹⁸F]FDG-PET/MRI compared with CT. We demonstrated in an homogeneous population of 152 patients that all patients with newly-diagnosed breast cancer and clinically-relevant lung nodules were detected at initial [¹⁸F]FDG-PET/MRI staging. However, due to the lower sensitivity of MRI in detecting lung nodules, a small proportion of clinically-relevant lung nodules were missed. Thus, a supplemental low-dose chest CT after neoadjuvant therapy should be considered for backup.

Abstract

Purpose: The evaluation of the clinical relevance of missed lung nodules at initial staging of breast cancer patients in [¹⁸F]FDG-PET/MRI compared with CT. Methods: A total of 152 patients underwent an initial whole-body [¹⁸F]FDG-PET/MRI and a thoracoabdominal CT for staging. Presence, size, shape and location for each lung nodule in [¹⁸F]FDG-PET/MRI was noted. The reference standard was established by taking initial CT and follow-up imaging into account (a two-step approach) to identify clinically-relevant lung nodules. Patient-based and lesion-based data analysis was performed. Results: No patient with clinically-relevant lung nodules was missed on a patient-based analysis with MRI VIBE, while 1/84 females was missed with MRI HASTE (1%). Lesion-based analysis revealed 4/96 (4%, VIBE) and 8/138 (6%, HASTE) missed clinically-relevant lung nodules. The average size of missed lung nodules was 3.2 mm ± 1.2 mm (VIBE) and 3.6 mm ± 1.4 mm (HASTE) and the predominant location was in the left lower quadrant and close to the hilum. Conclusion: All patients with newly-diagnosed breast cancer and clinically-relevant lung nodules were detected at initial [¹⁸F]FDG-PET/MRI staging. However, due to the lower sensitivity in detecting lung nodules, a small proportion of clinically-relevant lung nodules were missed. Thus, supplemental low-dose chest CT after neoadjuvant therapy should be considered for backup.

Complications and satisfaction in transwomen receiving breast augmentation: short- and long-term outcomes

BACKGROUND

To achieve long-term improvement in health care of transgender women, it is necessary to analyze all aspects of gender-confirming surgery, especially the relation of risks and benefits occurring in these procedures. While there are many studies presenting data on the urologic part of the surgery, there are just few data about complications and satisfaction with breast augmentation.

METHODS

This is a retrospective study using parts of the BREAST-Q Augmentation Questionnaire and additional questions for symptoms of capsular contracture and re-operations and analyzing archived patient records of all transwomen which were operated at University Hospital Essen from 2007 to 2020.

RESULTS

99 of these 159 patients (62%) completed the questionnaire after a median time of 4 years after surgery. Breast augmentation led to re-operations due to complications in 5%. The rate of capsular contracture (Baker Grad III-IV) in this population was 3%. Most patients (75%) rated high scores of satisfaction with outcome (more than 70 points) and denied to have restrictions due to their implants in their everyday life. All patients reported an improvement in their quality of life owing to breast augmentation.

CONCLUSION

Breast augmentation by inserting silicon implants is a safe surgical procedure which takes an important part in reducing gender dysphoria.

Systematic Evaluation of HLA-G 3'Untranslated Region Variants in Locally Advanced, Non-Metastatic Breast Cancer Patients: UTR-1, 2 or UTR-4 are Predictors for Therapy and Disease Outcome

Despite major improvements in diagnostics and therapy in early as well as in locally advanced breast cancer (LABC), metastatic relapse occurs in about 20% of patients, often explained by early micro-metastatic spread into bone marrow by disseminated tumor cells (DTC). Although neoadjuvant chemotherapy (NACT) has been a successful tool to improve overall survival (OS), there is growing evidence that various environmental factors like the non-classical human leukocyte antigen-G (HLA-G) promotes cancer invasiveness and metastatic progression. HLA-G expression is associated with regulatory elements targeting certain single-nucleotide polymorphisms (SNP) in the HLA-G 3’ untranslated region (UTR), which arrange as haplotypes. Here, we systematically evaluated the impact of HLA-G 3’UTR polymorphisms on disease status, on the presence of DTC, on soluble HLA-G levels, and on therapy and disease outcome in non-metastatic LABC patients. Although haplotype frequencies were similar in patients (n = 142) and controls (n = 204), univariate analysis revealed that the UTR-7 haplotype was related to patients with low tumor burden, whereas UTR-4 was associated with tumor sizes >T1. Furthermore, UTR-4 was associated with the presence of DTC, but UTR-3 and UTR-7 were related to absence of DTC. Additionally, increased levels of soluble HLA-G molecules were found in patients carrying UTR-7. Regarding therapy and disease outcome, univariate and multivariate analysis highlighted UTR-1 or UTR-2 as a prognostic parameter indicative for a beneficial course of disease in terms of complete response towards NACT or progression-free survival (PFS). At variance, UTR-4 was an independent risk factor for a reduced OS besides already known parameters. Taken into account the most common HLA-G 3’UTR haplotypes (UTR-1–UTR-7, UTR-18), deduction of the UTR-1/2/4 haplotypes to specific SNPs revealed that the +3003C variant, unique for UTR-4, seemed to favor a detrimental disease outcome, while the +3187G and +3196G variants, unique for UTR-1 or UTR-2, were prognostic parameters for a beneficial course of disease. In conclusion, these data suggest that the HLA-G 3’UTR variants +3003C, +3187G, and +3196G are promising candidates for the prediction of therapy and disease outcome in LABC patients.

Abstract P2-02-04: In early breast cancer, the ratios of neutrophils, monocyctes and platelets to lymphocytes significantly correlate with the presence of subsets of circulating tumor cells in blood and disseminated tumor cells in the bone marrow

Background: Circulating tumor cells (CTCs) are the precursors of metastasis and while travelling through the peripheral blood, they crosstalk with different types of blood cells before they finally reach distant organs to settle down as disseminated tumor cells (DTCs). Proinflammatory markers include the neutrophil lymphocyte ratio (NLR), the platelet lymphocyte ratio (PLR) as well as the monocyte lymphocyte ratio (MLR) and the presence of tumor cells as well as specific proinflammatory markers are two independent predictors of worse outcome in breast cancer (BC). However, little is known about the correlation between NLR, PLR, MLR and subsets of CTCs as well as DTCs in early, non-metastatic BC. Here we evaluated the correlation of NLR, PLR, MLR and the presence of epithelial CTCs (eCTCs), CTCs in epithelial mesenchymal transition (EMT-CTCs) as well as DTCs to better identify patients at risk, to monitor treatment reponse and probably adjust therapeutic options. Methods: The counts of peripheral neutrophils, lymphocytes, monocytes and platelets to determine NLR, PLR and MLR as well as clinicopathological data during diagnosis were retrospectively recorded for 171 patients (pts) diagnosed with BC from July 2006 to December 2012, before the start of therapy. NLR, PLR and MLR were calculated from peripheral blood cell counts and their optimal cutoff levels were determined by the 75% percentile resulting in the following values: NLR: 3.13, MLR: 0.39 and PLR: 222.3, respectively. 170/171 pts were analyzed for DTCs by immunocytochemistry using the pan-cytokeratin antibodyA45-B/B3 (Clodronate intake was recommended in case of DTC-positivity). CTCs were determined in 155/171 pts applying positive immunomagnetic selection using the AdnaTest BreastCancerSelect. The recovered cDNA was tested for the presence of eCTCs and EMT-CTCs using the AdnaTests BreastCancerDetect and EMTDetect. Pts were considered CTC-positive if at least one of the two tests were positive. Statistical analysis included descriptive reporting, U-test for group differences, Rho correlations for dependencies and Fisher's chi-square test for distributional differences. Rho correlations were used to assess the relationship between NLR, PLR, MLR and tumor cells as well as progression-free survival (PFS) and overall survival (OS). Results: DTCs were detected in 34% of the pts and at least one CTC-subtype was found in 28% of the pts. Whereas the presence of DTCs was not associated with PFS or OS, the presence of CTCs significantly correlated with a shorter PFS (p=0.046) and OS (p=0.018). However, neither eCTCs nor EMT-CTSs alone were of prognostic significance. Enhanced lymphocyte (p=0.025) and monocyte counts (p=0.039) as well as a low PLR (p=0.032) significantly correlated with a reduced PFS in pts still alive whereas an enhanced MLR showed a high correlation with a shorter PFS (p=0.007) and OS (p=0.021) in deceased pts. Whereas MLR significantly correlated with the presence of EMT-CTCs (p=0.045), the presence of eCTCs significantly associated with an elevated NLR (p=0.003) and enhanced lymphocyte (p=0.007) as well as monocyte counts (p=0.012). No significant correlations were found for NLR, PLR and MLR with DTCs, however, DTC-positive pts, harboring a lower PLR, had a significant shorter OS (p=0.043). Conclusion: Here we show that proinflammatory markers in blood are closely related to the presence of different CTC subsets in early BC while no direct correlation was found for tumor cell spread to the bone. These findings might improve the prognostication of these pts and probably help to monitor response to therapy and adjust treatment options.

Citation Format: Sabine Kasimir-Bauer, Ebru Karaaslan, Olaf Hars, Ann-Kathrin Bittner, Oliver Hoffmann, Rainer Kimmig. In early breast cancer, the ratios of neutrophils, monocyctes and platelets to lymphocytes significantly correlate with the presence of subsets of circulating tumor cells in blood and disseminated tumor cells in the bone marrow [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-02-04.

Free-breathing 3D Stack of Stars GRE (StarVIBE) sequence for detecting pulmonary nodules in 18F-FDG PET/MRI

BACKGROUND

The free-breathing T1-weighted 3D Stack of Stars GRE (StarVIBE) MR sequence potentially reduces artifacts in chest MRI. The purpose of this study was to evaluate StarVIBE for the detection of pulmonary nodules in ¹⁸F-FDG PET/MRI.

MATERIAL AND METHODS

In this retrospective analysis, conducted on a prospective clinical trial cohort, 88 consecutive women with newly diagnosed breast cancer underwent both contrast-enhanced whole-body ¹⁸F-FDG PET/MRI and computed tomography (CT). Patients' chests were examined on CT as well as on StarVIBE and conventional T1-weighted VIBE and T2-weighted HASTE MR sequences, with CT serving as the reference standard. Presence, size, and location of all detectable lung nodules were assessed. Wilcoxon test was applied to compare nodule features and Pearson's, and Spearman's correlation coefficients were calculated.

RESULTS

Out of 65 lung nodules detected in 36 patients with CT (3.7 ± 1.4 mm), StarVIBE was able to detect 31 (47.7%), VIBE 26 (40%) and HASTE 11 (16.8%), respectively. Overall, CT showed a significantly higher detectability than all MRI sequences combined (65 vs. 36, difference 44.6%, p < 0.001). The VIBE showed a significantly better detection rate than the HASTE (23.1%, p = 0.001). Detection rates between StarVIBE and VIBE did not significantly differ (7.7%, p = 0.27), but the StarVIBE showed a significant advantage detecting centrally located pulmonary nodules (66.7% vs. 16.7%, p = 0.031). There was a strong correlation in nodule size between CT and MRI sequences (HASTE: ρ = 0.80, p = 0.003; VIBE: ρ = 0.77, p < 0.001; StarVIBE: ρ = 0.78, p < 0.001). Mean image quality was rated as good to excellent for CT and MRI sequences.

CONCLUSION

The overall lung nodule detection rate of StarVIBE was slightly, but not significantly, higher than conventional T1w VIBE and significantly higher than T2w HASTE. Detectability of centrally located nodules is better with StarVIBE than with VIBE. Nevertheless, all MRI analyses demonstrated considerably lower detection rates for small lung nodules, when compared to CT.

Prospective comparison of CT and 18F-FDG PET/MRI in N and M staging of primary breast cancer patients: Initial results

Objectives

To compare the diagnostic accuracy of contrast-enhanced thoraco-abdominal computed tomography and whole-body ¹⁸F-FDG PET/MRI in N and M staging in newly diagnosed, histopathological proven breast cancer.

Material and methods

A total of 80 consecutive women with newly diagnosed and histopathologically confirmed breast cancer were enrolled in this prospective study. Following inclusion criteria had to be fulfilled: (1) newly diagnosed, treatment-naive T2-tumor or higher T-stage or (2) newly diagnosed, treatment-naive triple-negative tumor of every size or (3) newly diagnosed, treatment-naive tumor with molecular high risk (T1c, Ki67 >14%, HER2neu over-expression, G3). All patients underwent a thoraco-abdominal ceCT and a whole-body ¹⁸F-FDG PET/MRI. All datasets were evaluated by two experienced radiologists in hybrid imaging regarding suspect lesion count, localization, categorization and diagnostic confidence. Images were interpreted in random order with a reading gap of at least 4 weeks to avoid recognition bias. Histopathological results as well as follow-up imaging served as reference standard. Differences in staging accuracy were assessed using Mc Nemars chi² test.

Results

CT rated the N stage correctly in 64 of 80 (80%, 95% CI:70.0–87.3) patients with a sensitivity of 61.5% (CI:45.9–75.1), a specificity of 97.6% (CI:87.4–99.6), a PPV of 96% (CI:80.5–99.3), and a NPV of 72.7% (CI:59.8–82.7). Compared to this, ¹⁸F-FDG PET/MRI determined the N stage correctly in 71 of 80 (88.75%, CI:80.0–94.0) patients with a sensitivity of 82.1% (CI:67.3–91.0), a specificity of 95.1% (CI:83.9–98.7), a PPV of 94.1% (CI:80.9–98.4) and a NPV of 84.8% (CI:71.8–92.4). Differences in sensitivities were statistically significant (difference 20.6%, CI:-0.02–40.9; p = 0.008). Distant metastases were present in 7/80 patients (8.75%). ¹⁸ F-FDG PET/MRI detected all of the histopathological proven metastases without any false-positive findings, while 3 patients with bone metastases were missed in CT (sensitivity 57.1%, specificity 95.9%). Additionally, CT presented false-positive findings in 3 patients.

Conclusion

¹⁸F-FDG PET/MRI has a high diagnostic potential and outperforms CT in assessing the N and M stage in patients with primary breast cancer.

Prospective comparison of the diagnostic accuracy of 18F-FDG PET/MRI, MRI, CT, and bone scintigraphy for the detection of bone metastases in the initial staging of primary breast cancer patients

OBJECTIVES

To compare the diagnostic performance of [18F]FDG PET/MRI, MRI, CT, and bone scintigraphy for the detection of bone metastases in the initial staging of primary breast cancer patients.

MATERIAL AND METHODS

A cohort of 154 therapy-naive patients with newly diagnosed, histopathologically proven breast cancer was enrolled in this study prospectively. All patients underwent a whole-body [18F]FDG PET/MRI, computed tomography (CT) scan, and a bone scintigraphy prior to therapy. All datasets were evaluated regarding the presence of bone metastases. McNemar χ2 test was performed to compare sensitivity and specificity between the modalities.

RESULTS

Forty-one bone metastases were present in 7/154 patients (4.5%). Both [18F]FDG PET/MRI and MRI alone were able to detect all of the patients with histopathologically proven bone metastases (sensitivity 100%; specificity 100%) and did not miss any of the 41 malignant lesions (sensitivity 100%). CT detected 5/7 patients (sensitivity 71.4%; specificity 98.6%) and 23/41 lesions (sensitivity 56.1%). Bone scintigraphy detected only 2/7 patients (sensitivity 28.6%) and 15/41 lesions (sensitivity 36.6%). Furthermore, CT and scintigraphy led to false-positive findings of bone metastases in 2 patients and in 1 patient, respectively. The sensitivity of PET/MRI and MRI alone was significantly better compared with CT (p < 0.01, difference 43.9%) and bone scintigraphy (p < 0.01, difference 63.4%).

CONCLUSION

[18F]FDG PET/MRI and MRI are significantly better than CT or bone scintigraphy for the detection of bone metastases in patients with newly diagnosed breast cancer. Both CT and bone scintigraphy show a substantially limited sensitivity in detection of bone metastases.

KEY POINTS

• [18F]FDG PET/MRI and MRI alone are significantly superior to CT and bone scintigraphy for the detection of bone metastases in patients with newly diagnosed breast cancer. • Radiation-free whole-body MRI might serve as modality of choice in detection of bone metastases in breast cancer patients.

Comparison of nodal staging between CT, MRI, and [18F]-FDG PET/MRI in patients with newly diagnosed breast cancer

PURPOSE

To compare CT, MRI, and [¹⁸F]-fluorodeoxyglucose positron emission tomography ([¹⁸F]-FDG PET/MRI) for nodal status, regarding quantity and location of metastatic locoregional lymph nodes in patients with newly diagnosed breast cancer.

MATERIALS AND METHODS

One hundred eighty-two patients (mean age 52.7 ± 11.9 years) were included in this prospective double-center study. Patients underwent dedicated contrast-enhanced chest/abdomen/pelvis computed tomography (CT) and whole-body ([¹⁸F]-FDG PET/) magnet resonance imaging (MRI). Thoracal datasets were evaluated separately regarding quantity, lymph node station (axillary levels I-III, supraclavicular, internal mammary chain), and lesion character (benign vs. malign). Histopathology served as reference standard for patient-based analysis. Patient-based and lesion-based analyses were compared by a McNemar test. Sensitivity, specificity, positive and negative predictive values, and accuracy were assessed for all three imaging modalities.

RESULTS

On a patient-based analysis, PET/MRI correctly detected significantly more nodal positive patients than MRI (p < 0.0001) and CT (p < 0.0001). No statistically significant difference was seen between CT and MRI. PET/MRI detected 193 lesions in 75 patients (41.2%), while MRI detected 123 lesions in 56 patients (30.8%) and CT detected 104 lesions in 50 patients, respectively. Differences were statistically significant on a lesion-based analysis (PET/MRI vs. MRI, p < 0.0001; PET/MRI vs. CT, p < 0.0001; MRI vs. CT, p = 0.015). Subgroup analysis for different lymph node stations showed that PET/MRI detected significantly more lymph node metastases than MRI and CT in each location (axillary levels I-III, supraclavicular, mammary internal chain). MRI was superior to CT only in axillary level I (p = 0.0291).

CONCLUSION

[¹⁸F]-FDG PET/MRI outperforms CT or MRI in detecting nodal involvement on a patient-based analysis and on a lesion-based analysis. Furthermore, PET/MRI was superior to CT or MRI in detecting lymph node metastases in all lymph node stations. Of all the tested imaging modalities, PET/MRI showed the highest sensitivity, whereas CT showed the lowest sensitivity, but was most specific.

Association between mammographic breast density and achievement of a pathologic complete remission (pCR) after neoadjuvant chemotherapy (NACT) for early breast cancer (EBC)

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Background: Neoadjuvant chemotherapy (NACT) is indicated in early breast cancer (EBC) with an unfavorable tumor biology. Achievement of pathologic complete remission (pCR) after NACT is indicating an improved prognosis. An association between pCR and mammographic breast density as defined by BIRADS (Breast Imaging Reporting and Data System) could be demonstrated. However, the definition of mammographic breast density by the American College of Radiology (ACR) is widely used worldwide and data regarding an association of breast density by this definition and pCR after NACT are missing. Methods: We conducted a retrospective analysis among patients who had received neoadjuvant chemotherapy (NACT) for EBC and had available data regarding mammographic breast density as defined by ACR before therapy, pCR, age, estrogen and progesterone receptor (ER, PR) status, HER2neu status and grading were included. An association between mammographic breast density (ACR) and pCR was analyzed. Results: 185 patients were included in this analysis, 35.7% of whom achieved a pCR. Mammographic breast density was ACR 1 in 15.1%, ACR 2 in 41.6%, ACR3 in 38.4% and ACR 4 in 4.9% of the patients. A negative correlation (Spearman-Rho) between mammographic breast density and pCR (correlation coefficient (CC) -0.240) was highly statistically significant (p = 0.001). The association of decreasing pCR rates with increasing mammographic breast density (pCR rates by ACR 1: 53.6%, ACR 2: 41.6, ACR 3: 25.4% and 11.1 %) was statistically significant (Chi-Square, p = 0.013). These results were independent of age, ER status, PR status, HER2neu status and grading. Conclusions: In our analysis higher mammographic breast density as defined by ACR was significantly correlated with a lower chance of achieving a pCR after NACT. Although this result has to be interpreted with caution due to the small sample size and the retrospective character of our investigation, it is completely in line with other investigations using other definitions of mammographic breast density. The pathophysiological cause of this association should be further elucidated to reveal potential mechanisms of treatment resistance.

The role of Ki67 in involved lymph nodes as a predictive biomarker for response to neoadjuvant chemotherapy in patients with early breast cancer

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Background: Neoadjuvant chemotherapy (NACT) is a standard in early breast cancer (EBC) with an unfavorable tumor biology and pathologic complete remission (pCR) after NACT is indicating an improved prognosis. Ki67 is well established as a prognostic and predictive biomarker in early breast cancer and the association of high Ki67-results in breast tumors at the time of initial diagnosis and pCR after NACT is used for decision making for versus against NACT in daily routine in many countries. Data about associations of Ki67 in involved lymph nodes and response to NACT are missing. Methods: We conducted a retrospective analysis among patients in our database who had received NACT for EBC, had lymph node involvement verified by core cut biopsy and available data for pCR, age, estrogen and progesterone receptor (ER, PR) status, HER2neu status, Ki67 in the breast tumor and grading. Patients treated in clinical studies were excluded. Ki67 was measured in the archived material of biopsies from involved lymph nodes and the association between Ki67 in involved lymph nodes and response to neoadjuvant chemotherapy was analyzed. Results: 52 patients were included with regard to the criteria mentioned above, 21 had to be excluded because there was not enough lymph node biopsy material for Ki67 analysis. 7 (22.6) of the remaining 31 patients achieved a pCR and 11 (35.5%) achieved a nodal conversion to ypN0. Median Ki67 was 35% [3%, 85%] in involved lymph nodes and 40% [10%, 90%] in the breast. There was no significant correlation (Spearman Rho) between Ki67 in involved lymph nodes and pCR whereas there was for Ki67 in the breast (p = 0.046). The ROC-analysis resulted in a cut-off of 47% with the highest sensitivity for Ki67 in lymph nodes regarding prediction of nodal conversion. An analysis with a cut-off of Ki67 in involved lymph nodes of 47% predicted a nodal conversion in 60% of the cases (Chi-Square and Fisher’s Exact test; p = 0.0049). Conclusions: Our analysis supports Ki67 as a strong predictive biomarker regarding pCR after neoadjuvant chemotherapy. Although high Ki67 expression in involved lymph nodes is significantly associated with nodal conversion, it does not add clinically meaningful information to Ki67 in the breast.

Targeted breast surgery: Non-direct approach

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Background: Breast conserving surgery is the standard in T1-T3 primary breast cancer. The cosmetic result is very much depending upon the surgeon ́s experience, the tumor-size/breast ratio and the technique applied. We have proposed a nomogram earlier (1) which has been cited earlier by the American Society of Breast Surgeons Consensus Conference as a concept for avoidance of re-excisions and achievement of a favorable aesthetic result. Our nomogram proposed 5 simple oncoplastic techniques to handle the vast majority of breast cancer cases, with high rates of free margins. However, these techniques all used direct access to the mammary gland through the skin above the tumor, leaving permanent scars in the visible skin of the breast. To avoid this, we now have chosen a more natural access to the mammary gland along natural transitions and Langerhans´s skin lines in this prospective open-label study. Methods: We conducted a prospective open-arm study including all primary invasive and non-invasive breast cancer cases of tumor stages AJCC 0-III A (Version 8.0). Non-palbable tumors and those undergoing neoadjuvant chemotherapy had to be marked by a wire and clipped before. Intraoperative ultrasound was applied before skin incision and after removal of the tumor including ultrasound of the specimen to confirm clear margins). Resection was performed as a segmentectomy and SLN biopsy and axillary clearance was done according to national guidelines. Access to the tumor was chosen in a non-direct approach according to the proximity of the tumor to one of the following natural transitions: 1. areola 2. axillary line 3. inframammary fold. Results: 84 patients with breast conserving targeted breast surgery with a "non-direct to the tumor approach" have been enrolled so far. 76 patients had primary surgery with stage distribution as follows: Tis (1), T1a (3), T1b (8), T1c (30), T2 (30), T3 (4) and T4b(1). 8 patients had neoadjuvant chemotherapy with stage distribution as follows: ypT0 (3), ypT1a (2), ypT1c (1) and ypT2 (2). Histopathology was predominantly invasive-ductal breast cancer (70), followed by invasive-lobular (6), ductulo-lobular (5), invasive- ductal and pure DCIS (1), invasive-ductal and mucinous (1) and mucinous only (1). After first surgery according to our nomogram 77 patients had a tumor resection with free margins and 7 with involved margins, thus 91,6 % tumors were resected with free margins at first surgery. The remaining 8,4 % of cases were margin-free after second surgery. Conclusions: Scars were not visible on the surface of the breast outside of natural transitions and rate of free margins was high with targeted breast surgery at a rate of 91,6 % without any cosmetic impairment due to the remote natural access to the mammary gland. Patient-reported outcome in detail has been evaluated by validated questionnaires and demonstrated a high satisfaction with scar pattern, volume and symmetry.

Determining the axillary nodal status with four current imaging modalities including 18F-FDG PET/MRI in newly diagnosed breast cancer: A comparative study using histopathology as reference standard

Purpose: To compare breast magnetic resonance imaging (MRI), thoracal MRI, thoracal 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/MRI and axillary sonography for the detection of axillary lymph node metastases in women with newly diagnosed breast cancer. Materials and Methods: This prospective double-center study included patients with newly diagnosed breast cancer between March 2018 and December 2019. Patients underwent thoracal (18F-FDG PET/)MRI, axillary sonography, and dedicated prone breast MRI. Datasets were evaluated separately regarding nodal status (nodal+ vs. nodal-). Histopathology served as reference standard in all patients. The diagnostic performance of breast MRI, thoracal MRI, thoracal PET/MRI and axillary sonography in detecting nodal positive patients was tested by creating receiver-operating-characteristic curves (ROC) with a calculated area under the curve (AUC). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for all four modalities. A McNemar test was used to assess differences. Results: 112 female patients (mean age 53.04 ± 12.6 years) were evaluated. Thoracal PET/MRI showed the highest ROC-AUC with a value of 0.892. The AUC for breast MRI, thoracal MRI and sonography were 0.782, 0.814 and 0.834, respectively. Differences between thoracal PET/MRI and axillary sonography, thoracal MRI and breast MRI were statistically significant (PET/MRI vs. axillary sonography, P = 0.01; PET/MRI vs. thoracal MRI, P = 0.02; PET/MRI vs. breast MRI, P = 0.03). PET/MRI showed the highest sensitivity (81.8%, 36/44) (95%-CI: 67.29-91.81%) while axillary sonography had the highest specificity (98.5%, 65/66), 95%-CI: 91.84-99.96%). Conclusion: 18F-FDG PET/MRI outperforms axillary sonography, breast MRI and thoracal MRI in determining the axillary lymph node status. In a clinical setting, the combination of 18F-FDG PET/MRI and axillary sonography might be considered to provide even more accuracy in diagnosis.

Soluble Neuropilin-1 is an independent marker of poor prognosis in early breast cancer

Background

Neuropilin-1 (NRP-1) is a transmembrane protein that acts as a multifunctional non-tyrosine kinase receptor with an established role in development and immunity. NRP-1 also regulates tumor biology, and high expression levels of tissue NRP-1 have been associated with a poor prognosis. Recently, ELISA-based quantification of soluble NRP-1 (sNRP-1) has become available, but little is known about the prognostic value of sNRP-1 in malignancies.

Materials and methods

We measured sNRP-1 in the serum of 509 patients with primary early breast cancer (BC) at the time of diagnosis using ELISA.

Results

Mean serum values of sNRP-1 were 1.88 ± 0.52 nmol/l (= 130.83 ± 36.24 ng/ml). SNRP-1 levels weakly correlated with age, and were higher in peri- and postmenopausal patients compared to premenopausal patients, respectively (p < 0.0001). Low levels of sNRP-1 were associated with a significant survival benefit compared to high sNRP-1 levels at baseline (p = 0.005; HR 1.94; 95%CI 1.23–3.06). These findings remained significant after adjustment for tumor stage including lymph node involvement, grading, hormone receptor, HER2 status, and age (p = 0.022; HR 1.78; 95%CI 1.09–2.91).

Conclusion

Our findings warrant further investigations into the prognostic and therapeutic potential of sNRP-1 in BC.

Prospective Correlation of Prognostic Immunohistochemical Markers With SUV and ADC Derived From Dedicated Hybrid Breast 18F-FDG PET/MRI in Women With Newly Diagnosed Breast Cancer

PURPOSE

The aim of this study was to correlate prognostically relevant immunohistochemical parameters of breast cancer with simultaneously acquired SUVs and apparent diffusion coefficient (ADC) values derived from hybrid breast PET/MRI.

PATIENTS AND METHODS

Fifty-six women with newly diagnosed, therapy-naive, histologically proven breast cancer (mean age, 54.1 ± 12.0 years) underwent dedicated prone 18F-FDG breast PET/MRI. Diffusion-weighted imaging (b-values: 0, 500, 1000 s/mm2) was performed simultaneously with the PET acquisition. A region of interest encompassing the entire primary tumor on each patient's PET/MRI scan was used to determine the glucose metabolism represented by maximum and mean SUV as well as into corresponding ADC maps to assess tumor cellularity represented by mean and minimum ADC values. Histopathological tumor grading and prognostically relevant immunohistochemical markers, that is, Ki67, progesterone receptor, estrogen receptor, and human epidermal growth factor receptor 2 (HER2), were assessed. Pearson correlation coefficients were calculated to compare SUV and ADC values as well as the immunohistochemically markers and molecular subtype. For the comparison with the tumor grading, a Wilcoxon test was used.

RESULTS

A significant inverse correlation between SUV and ADC values derived from breast PET/MRI (r = -0.49 for SUVmean vs ADCmean; r = -0.43 for SUVmax vs ADCmin; both P's < 0.001) was found. Tumor grading and Ki67 both showed a positive correlation with SUVmean from breast PET/MRI (r = 0.37 and r = 0.32, P < 0.01). For immunohistochemical markers, HER2 showed an inverse correlation with ADC values from breast PET/MRI (r = -0.35, P < 0.01). Molecular subtypes significantly correlate with SUVmax and SUVmean (r = 0.52 and r = 0.42, both P's < 0.05). In addition, estrogen receptor expression showed an inverse correlation with SUVmax and SUVmean from breast PET/MRI (r = -0.45 and r = -0.42, P < 0.001).

CONCLUSIONS

The present data show a correlation between increased glucose metabolism, cellularity, tumor grading, estrogen and HER2 expression, as well as molecular subtype of breast cancer primaries. Hence, simultaneous 18F-FDG PET and diffusion-weighted imaging from hybrid breast PET/MRI may serve as a predictive tool for identifying high-risk breast cancer patients in initial staging and guide-targeted therapy.

Abstract PS1-11: Natural transition targeted surgery

Background: Breast conserving surgery is the standard in T1-T3 primary breast cancer. The cosmetic result is very much depending on the surgeon´s experience, the tumor-size/breast ratio and the technique applied. To improve cosmetic outcome and reduce repeated surgery, we have proposed a nomogram earlier (1) which has been cited by the American Society of Breast Surgeons Consensus Conference (2). In this nomogram, we proposed 5 simple oncoplastic techniques to handle the vast majority of breast cancer cases with a good cosmetic result. However, these techniques used direct access to the mammary gland, leaving scars in the visible skin of the breast. To avoid this, we chose a more natural access to the mammary gland at the natural transitions. Methods: We conducted a prospective open-arm study including all primary invasive and non-invasive breast cancer cases of tumor stages AJCC 0-III A (Version 8.0). Access to the tumor was chosen according to the proximity of the tumor to one of the following natural transitions (Areola, Lateral Insertion of the breast, inframmary fold): Non-palpable tumors and those undergoing neoadjuvant chemotherapy had to be marked by a wireand clippes before. Intraoperative ultrasound was applied before skin incision and after removal of the tumour (ultrasound of the specimen to confirm clear margins). Resection was performed as a segmentectomy and SLN biopsy and axillary clearance was done according to current guidelines.Results: 84 patients with breast conserving NTT-surgery have been enrolled so far. 76 patients had primary surgery with stage distribution as follows: Tis (1), T1a (3), T1b (8), T1c (30), T2 (30), T3 (4) and T4b(1). 8 patients had neoadjuvant chemotherapy with stage distribution as follows: ypT0 (3), ypT1a(2), ypT1c(1) and ypT2 (2). Histopathology was predominantly invasive-ductal breast cancer (70), followed by invasive-lobular (6), ductulo-lobular (5), invasive-ductal and DCIS (1),invasive-ductal and mucinous (1) and mucinous only (1). After first surgery 77 patients had a tumor resection according to the nomogramm of NTT-surgery with free margins and 7 with involved margins, thus 91,6 % tumors were resected with free margins at first surgery. The remaining 8,4 % were margin-free after second surgery. Conclusion: Scars were not visible on the surface of the breast outside of natural transitions and rate of free margins was high at 91,6 % without impairment due to the remote access to the mammary gland. We report a high patient satisfaction. Patient-reported outcome in detail has been evaluated by validated questionnaires and will be presented onsite. References:1. Rezai M., Knispel S., Kellersmann S., Lax H., Kimmig R., Kern P: Systematization of Oncoplastic Surgery: Selection of Surgical Techniques and Patient-Reported Outcome in a Cohort of 1,035 Patients, Ann Surg Oncol (2015) 22:3730-37372. Landercasper J. et al.: Toolbox to Reduce Lumpectomy Reoperations and Improve Cosmetic Outcome in Breast Cancer Patients: The America Society of Breast Surgeons Consensus Conference, Ann Surg Oncol 22, 3174-3183 (2015)

Citation Format: Peter Kern, Oliver Hoffmann, Ann-Kathrin Bittner, Rainer Kimmig, Mahdi Rezai, Ines Bücker, Alina Kessel. Natural transition targeted surgery [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-11.

Prospective evaluation of whole-body MRI and 18F-FDG PET/MRI in N and M staging of primary breast cancer patients

OBJECTIVES

To evaluate and compare the diagnostic potential of whole-body MRI and whole-body 18F-FDG PET/MRI for N and M staging in newly diagnosed, histopathologically proven breast cancer.

MATERIAL AND METHODS

A total of 104 patients (age 53.4 ± 12.5) with newly diagnosed, histopathologically proven breast cancer were enrolled in this study prospectively. All patients underwent a whole-body 18F-FDG PET/MRI. MRI and 18F-FDG PET/MRI datasets were evaluated separately regarding lesion count, lesion localization, and lesion characterization (malignant/benign) as well as the diagnostic confidence (5-point ordinal scale, 1-5). The N and M stages were assessed according to the eighth edition of the American Joint Committee on Cancer staging manual in MRI datasets alone and in 18F-FDG PET/MRI datasets, respectively. In the majority of lesions histopathology served as the reference standard. The remaining lesions were followed-up by imaging and clinical examination. Separately for nodal-positive and nodal-negative women, a McNemar chi2 test was performed to compare sensitivity and specificity of the N and M stages between 18F-FDG PET/MRI and MRI. Differences in diagnostic confidence scores were assessed by Wilcoxon signed rank test.

RESULTS

MRI determined the N stage correctly in 78 of 104 (75%) patients with a sensitivity of 62.3% (95% CI: 0.48-0.75), a specificity of 88.2% (95% CI: 0.76-0.96), a PPV (positive predictive value) of 84.6% % (95% CI: 69.5-0.94), and a NPV (negative predictive value) of 69.2% (95% CI: 0.57-0.8). Corresponding results for 18F-FDG PET/MRI were 87/104 (83.7%), 75.5% (95% CI: 0.62-0.86), 92.2% (0.81-0.98), 90% (0.78-0.97), and 78.3% (0.66-0.88), showing a significantly better sensitivity of 18F-FDG PET/MRI determining malignant lymph nodes (p = 0.008). The M stage was identified correctly in MRI and 18F-FDG PET/MRI in 100 of 104 patients (96.2%). Both modalities correctly staged all 7 patients with distant metastases, leading to false-positive findings in 4 patients in each modality (3.8%). In a lesion-based analysis, 18F-FDG PET/MRI showed a significantly better performance in correctly determining malignant lesions (85.8% vs. 67.1%, difference 18.7% (95% CI: 0.13-0.26), p < 0.0001) and offered a superior diagnostic confidence compared with MRI alone (4.1 ± 0.7 vs. 3.4 ± 0.7, p < 0.0001).

CONCLUSION

18F-FDG PET/MRI has a better diagnostic accuracy for N staging in primary breast cancer patients and provides a significantly higher diagnostic confidence in lesion characterization than MRI alone. But both modalities bear the risk to overestimate the M stage.

Circulating Tumor Cells Expressing the Prostate Specific Membrane Antigen (PSMA) Indicate Worse Outcome in Primary, Non-Metastatic Triple-Negative Breast Cancer

Background: We analyzed mRNA profiles of prostate cancer related genes in circulating tumor cells (CTCs) of primary, non-metastatic triple-negative breast cancer (TNBC) patients (pts) before and after neoadjuvant chemotherapy to elucidate the potential of prostate cancer targets in this BC subgroup.

Method: Blood from 41 TNBC pts (n = 41 before / 26 after therapy) was analyzed for CTCs applying the AdnaTest EMT-2/Stem Cell Select. Multimarker RT-qPCR allowed the detection of the prostate specific antigen PSA, the prostate specific membrane antigen PSMA, full-length androgen receptor (AR-FL), and AR splice-variant seven (AR-V7).

Results: Before therapy, at least one prostate cancer related gene was detected in 15/41 pts (37%). Notably, in 73% of AR-FL positive cases, AR-V7 was co-expressed. After therapy, CTCs of only one patient harbored prostate cancer related genes. AR-V7+ and PSMA+ CTCs significantly correlated with early relapse (p = 0.041; p = 0.00039) whereas PSMA+ CTCs also associated with a reduced OS (p = 0.0059). This correlation was confirmed for PSMA+ CTCs in univariate (PFS p = 0.002; OS p = 0.015), but not multivariate analysis.

Conclusion: Although CTCs that expressed prostate cancer related genes were eliminated by the given therapy, PSMA+ CTCs significantly identified pts at high risk for relapse. Furthermore, AR inhibition, often discussed for this BC subgroup, might not be successful in the primary setting of the disease since we identified AR-FL+ CTCs together with AR-V7+ CTCs, associated with therapeutic failure.

Molecular characterization of circulating tumour cells identifies predictive markers for outcome in primary, triple-negative breast cancer patients

mRNA profiles of circulating tumour cells (CTCs) were analysed in patients with triple‐negative breast cancer (TNBC) (pts) before (BT) and after therapy (AT) to identify additional treatment options. 2 × 5 mL blood of 51 TNBC pts and 24 non‐TNBC pts (HR+/HER2−; HR−/HER2+) was analysed for CTCs using the AdnaTest EMT‐2/Stem Cell Select™, followed by mRNA isolation and cDNA analysis for 17 genes by qPCR PIK3CA, AKT2, MTOR and the resistance marker AURKA and ERCC1 were predominantly expressed in all breast cancer subtypes, the latter ones especially AT. In TNBC pts, ERBB3, EGFR, SRC, NOTCH, ALK and AR were uniquely present and ERBB2+/ERBB3 + CTCs were found BT and AT in about 20% of cases. EGFR+/ERBB2+/ERBB3 + CTCs BT and ERBB2+/ERBB3 + CTCs AT significantly correlated with a shorter progression‐free survival (PFS; P = 0.01 and P = 0.02). Platinum‐based therapy resulted in a reduced PFS (P = 0.02) and an induction of PIK3CA expression in CTCs AT. In non‐TNBC pts, BT, the expression pattern in CTCs was similar. AURKA+/ERCC1 + CTCs were found in 40% of HR−/HER2 + pts BT and AT. In the latter group, NOTCH, PARP1 and SRC1 were only present AT and ERBB2 + CTCs completely disappeared AT. These findings might help to predict personalized therapy for TNBC pts in the future.

Sentinel-Lymphnode Biopsy in primary breast cancer: 99mTc versus ICG—A prospective, randomized trial

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Background: Sentinel-Lymphnode Biopsy (SLNB) is the standard procedure in primary breast cancer, routinely performed with 99mTechnetium radioactive tracers. Awareness of nuclear waste, costs and time consumption lead to the desire of breast surgeons to find safe and effective alternative options for detection of sentinel lymph nodes (SLN) in breast cancer and melanoma. Indocyaningreen is a tracer which emits fluorescence with near-infrared light of 780-810 nm when injected in the peritumoral or periareolar region, enabling surgeons to detect SLN and lymphatic pathways at the breast. Methods: We performed a prospective, randomized trial with patients with primary breast cancer. Both detection methods have been applied to patients of the study cohort comparing the preparation time, time to identify, concordance of the two methods and costs. Reference method was preoperative lymphszintigraphy. Results: 55 patients have been analyzed in this first report. Preparation time was 75,8 min (range 60-120 min) for 99mTc-tracer and a standard of 20 min for ICG. Time to identify SLN at a mean of 3,8 min(range 1-15 min) for 99mTc and 3 min (range 1-8 min) for ICG. Concordance rates were 98,2 % for the 1st SLN, 93,8 % both for 2nd and 3rd SLN. After neoadjuvant chemotherapy, all SLN have been been detected by both techniques, in 3 patients additional SLN have been found by ICG. Costs have been cut down to 1/10 with the use of ICG, coming up to saving of 27 000 US-$ per each 100 SLNB procedures performed. Conclusions: We report a high concordance rate between the 2 techniques - 99mTechnetium and ICG with near-infrared - for detection of SLN in breast cancer. Preparation time is cut down to less than 30 %, and costs to less the 10 % of radioactive labelling. Clinical trial information: 18-8054-BO .

CXCR4 and JUNB double-positive disseminated tumor cells are detected frequently in breast cancer patients at primary diagnosis

Background:

The chemokine receptor CXCR4 and the transcription factor JUNB, expressed on a variety of tumor cells, seem to play an important role in the metastatic process. Since disseminated tumor cells (DTCs) in the bone marrow (BM) have been associated with worse outcomes, we evaluated the expression of CXCR4 and JUNB in DTCs of primary, nonmetastatic breast cancer (BC) patients before the onset of any systemic treatment.

Methods:

Bilateral BM (10 ml) aspirations of 39 hormone receptor (HR)-positive, HER2-negative BC patients were assessed for the presence of DTCs using the following combination of antibodies: pan-cytokeratin (A45-B/B3)/CXCR4/JUNB. An expression pattern of the examined proteins was created using confocal laser scanning microscopy, Image J software and BC cell lines.

Results:

CXCR4 was overexpressed in cancer cells and DTCs, with the following hierarchy of expression: SKBR3 > MCF7 > DTCs > MDA-MB231. Accordingly, the expression pattern of JUNB was: DTCs > MDA-MB231 > SKBR3 > MCF7. The mean intensity of CXCR4 (6411 ± 334) and JUNB (27725.64 ± 470) in DTCs was statistically higher compared with BM hematopoietic cells (2009 ± 456, p = 0.001; and 11112.89 ± 545, p = 0.001, respectively). The (CXCR4+JUNB+CK+) phenotype was the most frequently detected [90% (35/39)], followed by the (CXCR4–JUNB+CK+) phenotype [36% (14/39)]. However, (CXCR4+JUNB–CK+) tumor cells were found in only 5% (3/39) of patients. Those patients harboring DTCs with the (CXCR4+JUNB+CK+) phenotype revealed lower overall survival (Cox regression: p = 0.023).

Conclusions:

(CXCR4+JUNB+CK+)-expressing DTCs, detected frequently in the BM of BC patients, seem to identify a subgroup of patients at higher risk for relapse that may be considered for close follow up.

Abstract P5-01-14: The combined blood analysis of cell-free DNA and genomic DNA of circulating tumor cells reveals additive value in hormone receptor-positive, HER2-negative metastatic breast cancer patients

Background: To gain comprehensive insights into the genomic complexity useful for therapy management in metastatic breast cancer (MBC), we aimed to isolate and analyze genomic DNA (gDNA) from circulating tumor cells (CTCs) and matched cell-free DNA (cfDNA) from a minimized blood volume. Methods: EDTA blood was drawn from 27 MBC patients with hormone receptor-positive and HER2 negative primary tumors at the time of disease progression. CTCs and CTC mRNA were isolated from 2 × 5 ml whole blood using the AdnaTest EMT2/StemCell Select/Detect. Plasma of CTC-depleted blood was used for cfDNA isolation. gDNA from CTCs was isolated from the mRNA-depleted CTC lysates using the AllPrep DNA/RNA Nano Kit prototype. CTC gDNA and cfDNA were analyzed with a customized QIAseq Targeted DNA Panel for Illumina with unique molecular indices (UMIs) analyzing AKT1, AR, BRCA1, BRCA2, EGFR, ERCC4, ERBB2, ERBB3, ESR1, FGFR1, KRAS, MUC16, PIK3CA, PIK3R1, PTEN, PTGFR and TGFB1. The library preparation protocol was slightly modified for the usage of CTC gDNA using the entire amount of the CTC gDNA eluate as input without pre-quantification followed by fragmentation and ligation with an increased number of adapters. All libraries were analyzed by paired-end sequencing on the Illumina NextSeq Sequencer with a NextSeq 550 System High-Output Kit, 2 × 150 bp reads with a mean coverage of 11000 x (CTC gDNA) and 8000 x (cfDNA). Consumables: QIAGEN, Germany. Results: Isolation of CTC gDNA and cfDNA was successfully established in a condensed workflow. The UMI coverage observed for cfDNA (2000 x) differed from the UMI coverage for CTC gDNA (500 x), resulting in dramatically increased lowest detectable allele frequency (AF) called with a confidence of 90% in CTC gDNA compared to cfDNA. On average, 6 CTC gDNA variants and 2 cfDNA variants were detected in each patient. Most variants were found in the MUC16 gene in both analytes. BRCA2 variants were the second most prevalent variants in CTC gDNA and cfDNA. PIK3CA and ESR1 variants were less common in CTC gDNA compared with cfDNA, while ERBB2 variants were only detected in CTC gDNA. 57% of all cfDNA variants (29/51) were recovered in the matched CTC gDNA, while 89% of all variants were unique in either CTC gDNA (125 variants) or cfDNA (22 variants). On average, the cfDNA variants with low AF (mean 15%) were not detected in CTC gDNA, while the cfDNA variants that were also found in CTC gDNA exhibited a mean AF of 44%. Similarly, the unique CTC gDNA variants had a mean AF of 23%, while the shared variants were prevalent with a mean AF of 47% in the CTC gDNA fraction. Comparing the patients, 11%/14% of the single CTC gDNA / cfDNA variants were detected in more than one patient, hence the majority of variants was patient-specific. The portion of patients without detectable cfDNA variants or CTC gDNA variants was 15% (4/27) / 11% (3/27), but combined analysis of CTC gDNA and cfDNA identified variants in 26 of all 27 MBC patients (96%). Conclusion: cfDNA and CTC gDNA showed additive variant information. Thus, it is advised to assess cfDNA and CTC gDNA variants to receive a comprehensive genomic picture that might enable to identify the most suitable therapy regimen in each individual patient in the future.

Citation Format: Corinna Keup, Ann-Kathrin Bittner, Oliver Hoffmann, Mitra Tewes, Markus Storbeck, Peter Hahn, Siegfried Hauch, Markus Sprenger-Haussels, Rainer Kimmig, Sabine Kasimir-Bauer. The combined blood analysis of cell-free DNA and genomic DNA of circulating tumor cells reveals additive value in hormone receptor-positive, HER2-negative metastatic breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-01-14.

Abstract P4-01-11: Circulating tumor cells expressing the prostate specific membrane antigen PSMA indicate worse outcome in triple-negative breast cancer patients at primary diagnosis

Background: Triple negative breast cancer (TNBC) is known for its aggressive behavior and poor prognosis since treatment options are limited. Specific biomarkers are urgently needed to treat patients (pts) accordingly. In this regard, circulating tumor cells (CTCs) are discussed to be an ideal surrogate marker for individualized treatment options. We here comprehensively analyzed mRNA profiles of CTCs from TNBC pts before and after neoadjuvant chemotherapy including the expression of prostate related genes [androgen receptor (AR), its splice variant ARV7, the prostate specific antigen (PSA) and the prostate specific membrane antigen (PSMA)] to further elucidate these markers as targets for personalized treatment. Methods: 2 × 5 ml blood of 34 TNBC pts before and 22 pts after therapy were analyzed for CTCs applying positive immunomagnetic selection using the AdnaTest EMT-2/Stem Cell Select (QIAGEN, Germany). Subsequently, cDNA was pre-amplified for specific genes using TaqMan PreAmp Master Mix according to in house designed assays. A 19 gene qPCR panel was performed including AKT2, ALK, AR, AURKA, BRCA1, EGFR, ERCC1, ERBB2, ERBB3, KIT, KRT5, MET, MTOR, NOTCH1, PARP1, PIK3CA, SRC, CD45 (leucocyte control) and GAPDH (housekeeping gene) as well as an internal reference. The cutoff was calculated, taking the false positive rate in healthy donors into account, and defined as Ct (cutoff) - Ct (sample) - [Ct (CD45cutoff) - Ct (CD45sample)]. Using the AdnaPanel Prostate Cancer (QIAGEN, Germany), cDNA was further analyzed for the expression profile of AR, ARV7, PSA and PSMA, respectively. Results: Before therapy, at least one of the prostate related genes was detected in 50% of the pts, resulting in the expression of AR in 35%, ARV7 in 24%, PSMA in 18%, and PSA in 15% of cases, respectively. Notably, in 75% of AR-positive cases, ARV7 was also expressed on CTCs. After therapy, prostate related genes were only detected in two pts, expressing AR, ARV7 and PSA (n=1) and AR (n=1), respectively. Before therapy, the presence of PSMA-positive CTCs alone (p=0.026) or in combination with ARwildtype/ARV7-positive CTCs (p=0.014) significantly correlated with early relapse. Interestingly, this expression pattern was highly related to the expression of genes belonging to the ERBB family (EGFR, ERBB2, ERBB3; p=0.034). Either ERRB family or PSMA expression on CTCs in TNBC was detected in about 70% of the cases analyzed with 90% relapses predicted. Conclusion: Although AR and its splice variant were detected on CTCs in one third of the pts before therapy, these markers do not seem to be relevant with regard to be considered as targets for additional treatment options. In contrast, although expressed in a minority of pts, PSMA-positive CTCs at primary diagnosis indicated worse outcome and should be included in CTC-multimarker panel analysis to identify pts at higher risk for relapse. This study is ongoing and the analysis of more pts will finally show whether these results can be confirmed.

Citation Format: Sabine Kasimir-Bauer, Corinna Keup, Oliver Hoffmann, Siegfried Hauch, Rainer Kimmig, Ann-Kathrin Bittner. Circulating tumor cells expressing the prostate specific membrane antigen PSMA indicate worse outcome in triple-negative breast cancer patients at primary diagnosis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-01-11.

High serum levels of periostin are associated with a poor survival in breast cancer

PURPOSE

Periostin is a secreted extracellular matrix protein, which was originally described in osteoblasts. It supports osteoblastic differentiation and bone formation and has been implicated in the pathogenesis of several human malignancies, including breast cancer. However, little is known about the prognostic value of serum periostin levels in breast cancer.

METHODS

In this study, we analyzed serum levels of periostin in a cohort of 509 primary, non-metastatic breast cancer patients. Disseminated tumor cell (DTC) status was determined using bone marrow aspirates obtained from the anterior iliac crests. Periostin levels were stratified according to several clinical parameters and Pearson correlation analyses were performed. Kaplan-Meier survival curves were assessed by using the log-rank (Mantel-Cox) test. To identify prognostic factors, multivariate Cox regression analyses were used.

RESULTS

Mean serum levels of periostin were 505 ± 179 pmol/l. In older patients (> 60 years), periostin serum levels were significantly increased compared to younger patients (540 ± 184 pmol/l vs. 469 ± 167 pmol/l; p < 0.0001) and age was positively correlated with periostin expression (p < 0.0001). When stratifying the cohort according to periostin serum concentrations, the overall and breast cancer-specific mortality were significantly higher in those patients with high serum periostin (above median) compared to those with low periostin during a mean follow-up of 8.5 years (17.7% vs. 11.4% breast cancer-specific death; p = 0.03; hazard ratio 1.65). Periostin was confirmed to be an independent prognostic marker for breast cancer-specific survival (p = 0.017; hazard ratio 1.79). No significant differences in serum periostin were observed when stratifying the patients according to their DTC status.

CONCLUSIONS

Our findings emphasize the relevance of periostin in breast cancer and reveal serum periostin as a potential marker for disease prediction, independent on the presence of micrometastases.

Re-Excision Rates in Breast-Conserving Surgery for Invasive Breast Cancer after Neoadjuvant Chemotherapy with and without the Use of a Radiopaque Tissue Transfer and X-ray System

Background

Significant re-excision rates in breast-conserving surgery (BCS) after neoadjuvant systemic chemotherapy may result from difficulties in defining the surgical target particularly in cases with excellent treatment response. Devices allowing an exact topographic localisation of the lesion in the resected tissue could reduce re-excision rates by optimising the intraoperative detection of involved margins.

Methods

80 patients with invasive breast cancer receiving BCS after neoadjuvant chemotherapy were included in this non-randomized case-control study. 40 patients with specimen radiography performed in a standard approach (control group) were compared to 40 patients with use of a radiopaque tissue transfer system (study group).

Results

19/80 (23.75%) patients required re-excision because of involved margins; among those, 14/40 (35%) were in the control group and 5/40 (12.5%) in the study group. The association between the use of the radiopaque tissue transfer system and the lower re-excision rate was statistically significant (p = 0.023).

Conclusion

Our analysis provides a rationale for the routine use of a radiopaque tissue transfer system for specimen radiography in BCS after neoadjuvant chemotherapy for invasive breast cancer in order to reduce re-excision rates.

Abstract 1369: Establishment of a workflow for analysis of mRNA and gDNA from circulating tumor cells, extracellular vesicles and cell-free DNA from the same blood sample to mirror the genomic and transcriptomic complexity in metastatic breast cancer patients

Background: Blood analytes derived from liquid biopsies are discussed as useful tools for therapy stratification and for monitoring of clonal evolution. To gain comprehensive insights into the genomic and transcriptomic complexity in metastatic breast cancer (MBC) useful for therapy management, we aimed to isolate and analyze mRNA and gDNA from circulating tumor cells (CTCs), mRNA from extracellular vesicles (EVs) and cell-free DNA (cfDNA) from the same blood sample with minimized volume in a condensed workflow.

Patients and Methods: EDTA blood (2x 9 ml) was drawn from 35 MBC patients with hormone receptor positive and HER2 negative primary tumor at time of disease progression and at two further consecutive staging time points. CTCs were isolated in duplicate from 5ml blood by immunomagnetic selection (AdnaTest EMT2/StemCell Select, QIAGEN). Plasma (4 ml) of the CTC-depleted blood was used for cfDNA isolation (QIAamp MinElute ccfDNA Kit, QIAGEN), plasma (4 ml) from the blood not used for CTC/cfDNA isolation was applied for EV isolation (exoRNeasy, QIAGEN). The mRNA purified from CTCs and EVs was analyzed by qPCR panel (AdnaPanel TNBC prototype, QIAGEN), while cfDNA was analyzed with a customized QIAseq Targeted DNA Panel for Illumina (QIAGEN) with unique molecular indices. We are working on a workflow to isolate gDNA from CTCs, starting from mRNA-depleted CTC lysates and analyzing the gDNA with a customized QIAseq Targeted DNA Panel. Isolation and mutation analysis of CTC gDNA was shown to be feasible in spiking experiments.

Results: Isolation of mRNA and gDNA from CTCs, mRNA from EVs and cfDNA was successfully established in a parallel workflow. CTC and EV mRNA profiles showed substantial differences synergizing with regard to their clinical relevance. Whereas overexpression of mTOR was related to therapy responsiveness in CTCs, mTOR signals in EVs related to therapy failure. ERBB2 overexpressing CTCs were found in one third of all MBC patients enabling new therapeutic options. Matched cfDNA revealed the appearance of pathogenic mutations (e.g. PIK3CA H1047R) across treatment indicating underlying resistance mechanisms. Moreover, we identified significant correlations of therapy outcome with the overexpression of transcripts/ presence of mutations in each of the isolated liquid biopsy analytes. Comparison of CTC gDNA and cfDNA is further conducted.

Conclusions: We were able to describe a complete workflow for parallel CTC mRNA, CTC gDNA, EV mRNA and cfDNA isolation from a minimized blood volume. In this research study each analyte showed synergistic potential for therapy management, thus the comprehensive picture of the genomic and transcriptomic complexity might in future enable to identify the most suitable therapy regiment in each individual patient.

Citation Format: Corinna Keup, Markus Storbeck, Peter Hahn, Siegfried Hauch, Markus Sprenger-Haussels, Ann-Kathrin Bittner, Oliver Hoffmann, Mitra Tewes, Rainer Kimmig, Sabine Kasimir-Bauer. Establishment of a workflow for analysis of mRNA and gDNA from circulating tumor cells, extracellular vesicles and cell-free DNA from the same blood sample to mirror the genomic and transcriptomic complexity in metastatic breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1369.

Targeted deep sequencing revealed variants in cell-free DNA of hormone receptor-positive metastatic breast cancer patients

Cell-free DNA (cfDNA) is described to mirror intratumoral heterogeneity and gives insight about clonal evolution for improved therapeutic decisions. We sequenced cfDNA of a hormone receptor-positive, HER2-negative metastatic breast cancer (MBC) cohort with a high coverage to examine the prevalence and relevance of any detected variant. cfDNA of 44 MBC patients was isolated, followed by library construction using a customized targeted DNA panel with integrated unique molecular indices analyzing AKT1, AR, BRCA1, BRCA2, EGFR, ERCC4, ERBB2, ERBB3, ESR1, FGFR1, KRAS, MUC16, PIK3CA, PIK3R1, PTEN, PTGFR, and TGFB1. CfDNA was sequenced on the NextSeq^® 550 platform (Illumina) and variants were analyzed with Ingenuity Variant Analysis (QIAGEN). We evaluated cfDNA variants in 40 of the 44 hormone receptor-positive and HER2-negative patients with a high mean coverage of 22,000×, resulting in MUC16, BRCA2, ERBB3, and AR variant calling in > 90% of the patients. 47% of all AR variants were pathogenic and at least one pathogenic or likely pathogenic variant was detected in each patient. A specific BRCA1 variant and > 3.5 pathogenic variants significantly associated with a reduced survival after diagnosis of metastasis. Longitudinal monitoring revealed an increase of pathogenic and likely pathogenic PIK3CA and ESR1 variant allele frequency under everolimus and exemestane, 8 months before proof of therapy failure by visual staging in one exemplary case. The identification of new variants with high prevalence, prognostic value, and dynamics under treatment by deep sequencing of cfDNA might empower sensitive monitoring and personalized therapeutic decisions.

Dissimilar patterns of tumor-infiltrating immune cells at the invasive tumor front and tumor center are associated with response to neoadjuvant chemotherapy in primary breast cancer

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are described as an important immune modulator in the tumor microenvironment and are associated with breast cancer (BC) outcome. The spatial analysis of TILs and TIL subtype distribution at the invasive tumor front (ITF) and the tumor center (TC) might provide further insights into tumor progression.

METHODS

We analyzed core biopsies from 87 pre-therapeutic BC patients for total TILs and the following subtypes: CD3+, CD4+, CD8+, CD20+ and CD68+ cells in correlation to clinicopathological parameters and disseminated tumor cells (DTCs) in the bone marrow.

RESULTS

TILs and TIL subtypes showed significantly different spatial distribution among both tumor areas. TILs, especially CD3+ T cells were associated with the tumor status and tumor grading. BC patients responding to neoadjuvant chemotherapy had significantly more TILs and CD3+ T cells at the TC. The presence of DTCs after NACT was related to CD4+ infiltration at the TC.

CONCLUSION

The dissimilar spatial association of TILs and TIL subtypes with clinicopathological parameters, NACT response and minimal residual disease underlines the necessity of detailed TIL analysis for a better understanding of immune modulatory processes.

Prognostic Value of RANKL/OPG Serum Levels and Disseminated Tumor Cells in Nonmetastatic Breast Cancer

PURPOSE

We assessed serum concentrations of the receptor activator of NFκB ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG), two proteins implicated in the development and progression of breast cancer, in 509 patients with primary, nonmetastatic breast cancer. Then the results were evaluated with regards to the occurrence of bone metastases, the presence of disseminated tumor cells (DTC) in the bone marrow, survival, and risk of developing metastatic disease.

EXPERIMENTAL DESIGN

Before surgery, two bone marrow aspirates were analyzed for DTC using density centrifugation followed by immunocytochemistry (pan-cytokeratin antibody A45-B/B3). RANKL and OPG levels in the serum were measured by ELISA.

RESULTS

RANKL levels were significantly lower in women >60 years (P < 0.0001) and RANKL/OPG ratios higher in lymph node-positive patients (P < 0.05). High OPG serum levels were associated with a higher risk of death from breast cancer [HR 1.94; 95% confidence interval (CI) 1.23-3.07; P = 0.005] and OPG was an independent prognostic marker for breast cancer-specific survival (BCSS; multivariate analyses, P = 0.035). RANKL levels were 33% higher (P < 0.0001) in DTC^pos patients (41%), whereas high levels were associated with a significantly better BCSS in DTC^neg patients as compared with low levels (HR 0.524; 95% CI 0.30-0.95; P = 0.04). RANKL serum levels were significantly increased in patients who developed bone metastases (P = 0.01) and patients within the highest quartile of RANKL had a significantly increased risk of developing bone metastases compared with those in the lowest (HR 4.62; 95% CI 1.49-14.34; P = 0.03).

CONCLUSIONS

These findings warrant further investigation as they provide a rationale for novel diagnostic or therapeutic approaches.

Elevated levels of extracellular vesicles are associated with therapy failure and disease progression in breast cancer patients undergoing neoadjuvant chemotherapy

Extracellular vesicles (EVs) have been discussed as a diagnostic tool for minimal residual disease (MRD) evaluation in breast cancer (BC) in addition to the analysis of circulating tumor cells (CTCs). Therefore, we investigated circulating EV levels as surrogate markers for disease monitoring and prediction of prognosis in primary, non-metastatic, locally advanced BC patients. EVs were enriched from blood samples of BC patients before and after neoadjuvant chemotherapy (NACT) and from healthy females. EV marker expression analysis was performed and EV sizes and concentrations were determined by nanoparticle tracking analysis. The results were associated with disease status, outcome and CTC presence, evaluated by gene expression analysis after enrichment. We demonstrated that i) the EV concentration was 40-fold higher in BC patients compared to healthy females, ii) the EV concentration increased during therapy, iii) an increased EV concentration pre-NACT was associated with therapy failure and iv) an elevated EV concentration post-NACT was associated with a reduced three-year progression-free and overall survival. Of note, residual stem cell-like and/or resistant CTCs after therapy were associated with a lower EV concentration post-NACT. Our study highlights that the concentration of EVs within BC blood samples may serve as a complementary parameter reflecting the status of MRD as well as therapy and disease outcome in parallel with CTC investigation.

Abstract 3152: Breast cancer-derived extracellular vesicles: clinical and prognostic impact

Background: Extracellular vesicles (EVs) are released from cancer cells into the tumor microenvironment, there participating in intercellular communication by altering recipient cell function. Breast cancer (BC) derived EVs are hypothesized to have an impact on tumor growth, immunosuppression or metastatic development, indicating analytical significance of EV concentrations in BC patients. For this reason, we investigated plasmatic EV numbers from locally advanced, neoadjuvant treated (NACT) BC patients in association with clinical parameters and prognostic impact.

Material and methods: Plasmatic extracellular vesicles were isolated using ExoQuick™ precipitation reagent (SBI Inc., Mountain View, CA, USA), according to manufacturer's instructions, from locally advanced BC patients before (n = 142) and after (n = 156) NACT as well as from healthy female controls (n = 16). Subsequently, number and EV particle size were analyzed using ZetaView Laser Scattering Video Microscope (Particle Metrix GmbH, Microtrac, Meerbusch, Germany). Samples were 1:50.000 in PBS pre-diluted to obtain particle concentrations of approx. 1 × 10⁁6 particles per ml. Circulating tumor cells (CTCs) and stem cell-like circulating tumor cells (slCTCs) were evaluated using the AdnaTests BreastCancer, StemCell and EMT, respectively (QIAGEN Hannover GmbH, Germany).

Results: EV particle concentrations (mean ± SEM in 10⁁9/ml) were significantly (p &lt; 0.0001) elevated in BC patients (n = 104, respectively) before (2370 ± 170) and after (3524 ± 523) NACT compared to healthy females (90 ± 19). Paired analysis before and after NACT revealed higher EV levels after NACT (p = 0.008). In association studies, high EV numbers before NACT were related to less differentiated carcinomas and to lymph node spread. ROC analysis showed optimal cut-off values of EV levels (i) before NACT: 3540 × 10⁁9/ml (sensitivity: 66.7%; specificity: 78.1%; AUC = 0.706) and (ii) after NACT: 2480 × 10⁁9/ml (sensitivity: 100%; specificity: 44,3%; AUC = 0.654). In Kaplan-Meier analysis, a decreased 3-year PFS was significantly associated with EV particle concentrations after NACT &gt; 2480 × 10⁁9/ml (p = 0.005). A reduced OS of BC patients was significantly associated with (i) EV levels before NACT &gt; 3540 × 10⁁9/ml) (p = 0.001) and (ii) EV levels after NACT &gt; 2480 × 109/ml) (p = 0.003). Decreased EV levels were found in BC patients after NACT with CTCs expressing ERCC1 (p = 0.025) or the stem cell marker ALDH1 (p = 0.004).

Conclusion: In conclusion, BC patients showed elevated plasmatic EV levels compared to healthy females, while increased EV levels after NACT might be due to therapeutic effects. The association between EV particle concentrations and clinical parameters as well as their prognostic impact on clinical outcome in BC indicate the importance of EVs as a mediator in the BC tumor microenvironment. Therefore, determination of plasmatic EV particle amount might serve as a biomarker for BC monitoring.

Citation Format: Lisa König, Vera Rebmann, Oliver Hoffmann, Ann-Kathrin Bittner, Bettina Wagner, Luis Felipe Santos Manvailer, Sabine Schramm, Agnes Bankfalvi, Bernd Giebel, Rainer Kimmig, Peter A. Horn, Sabine Kasimir-Bauer. Breast cancer-derived extracellular vesicles: clinical and prognostic impact. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3152.

Different prognostic value of circulating and disseminated tumor cells in primary breast cancer: Influence of bisphosphonate intake?

Disseminated tumor cells (DTCs) in the bone marrow (BM) and circulating tumor cells (CTCs) in blood of breast cancer patients (pts) are known to correlate with worse outcome. Here we demonstrate a different prognostic value of DTCs and CTCs and explain these findings by early clodronate intake. CTCs (n = 376 pts) were determined using the AdnaTest BreastCancer (Qiagen Hannover GmbH, Germany) and DTCs (n = 525 pts) were analyzed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. Clodronate intake was recommended in case of DTC-positivity. CTCs were detected in 22% and DTCs in 40% of the pts, respectively. DTCs were significantly associated with nodal status (p = 0.03), grading (p = 0.01), lymphangiosis (p = 0.03), PR status (p = 0.02) and clodronate intake (p < 0.0001), no significant associations were demonstrated for CTCs. CTCs significantly correlated with reduced PFS (p = 0.0227) and negative prognostic relevance was predominantly related to G2 tumors (p = 0.044), the lobular (p = 0.024) and the triple-negative subtype (p = 0.005), HR-negative pts (p = 0.001), postmenopausal women (p = 0.013) and patients who had received radiation therapy (p = 0.018). No prognostic significance was found for DTCs. Therefore early clodronate intake can improve prognosis of breast cancer patients and CTCs might be a high risk indicator for the onset of metastasis not limited to bone metastasis.

B3-lesions of the breast and cancer risk - an analysis of mammography screening patients

The use of mammography screening, followed by needle core biopsy (NCB), is associated with an increasing amount of invasive procedures. A considerable amount of specimens must be classified as lesions with uncertain malignant potential (B3-lesion). In these cases, an open biopsy is indicated for further diagnosis. We evaluated patients with B3-lesions to determine the risk of malignancy corresponding to the histopathological NCB results and the type of radiological lesion identified. A total of 95 patients participating in the German mammography screening program with a B3-lesion following NCB (104 B3-lesions in total) were included in our analysis. We analyzed the correlation between the initial histopathological findings from the NCB specimen and cancer risk. We further analyzed the correlations of malignant results with the type of mammographic lesion. In 23 cases (22%), histopathological examination following excision revealed a malignant lesion, including invasive and in situ carcinoma. The positive predictive value of the subgroups of B3-lesions ranged between 0.11 and 0.31; the B3-lesion associated with the highest cancer risk was the atypical ductal hyperplasia; however, no significant difference was observed between the B3-lesion subgroups (P=0.309) regarding the risk of malignancy. Comparing the different types of mammographic findings, such as radiological mass or microcalcifications, there was no significant difference in the risk for malignancy (P=0.379). The different types of B3-lesions did not exhibit differences in the risk for malignancy, and the morphological type of mammographic lesion does not appear to be correlated with cancer risk; therefore, our results underline the need for open biopsy in patients with B3-lesions following NCB.

Does primary neoadjuvant systemic therapy eradicate minimal residual disease? Analysis of disseminated and circulating tumor cells before and after therapy

BACKGROUND

Patients with breast cancer (BC) undergoing neoadjuvant chemotherapy (NACT) may experience metastatic relapse despite achieving a pathologic complete response. We analyzed patients with BC before and after NACT for disseminated tumor cells (DTCs) in the bone marrow(BM); comprehensively characterized circulating tumor cells (CTCs), including stem cell-like CTCs (slCTCs), in blood to prove the effectiveness of treatment on these cells; and correlated these findings with response to therapy, progression-free survival (PFS), and overall survival (OS).

METHODS

CTCs (n = 135) and slCTCs (n = 91) before and after NACT were analyzed using the AdnaTest BreastCancer, AdnaTest TumorStemCell, and epithelial-mesenchymal transition (QIAGEN Hannover GmbH Germany). The expression of estrogen receptor, progesterone receptor, and the resistance marker excision repair cross-complementing rodent repair deficiency, complementation group 1 (ERCC1), nuclease were studied in separate single-plex reverse transcription polymerase chain reaction experiments. DTCs were evaluated in 142 patients before and 165 patients after NACT using the pan-cytokeratin antibody A45-B/B3 for immunocytochemistry.

RESULTS

The positivity rates for DTCs, CTCs, and slCTCs were 27 %, 24 %, and 51 % before and 20 %, 8 %, and 20 % after NACT, respectively. Interestingly, 72 % of CTCs present after therapy were positive for ERCC1, and CTCs before (p = 0.005) and after NACT (p = 0.05) were significantly associated with the presence of slCTCs. Whereas no significant associations with clinical parameters were found for CTCs and slCTCs, DTCs were significantly associated with nodal status (p = 0.03) and histology (0.046) before NACT and with the immunohistochemical subtype (p = 0.02) after NACT. Univariable Cox regression analysis revealed that age (p = 0.0065), tumor size before NACT (p = 0.0473), nodal status after NACT (p = 0.0137), and response to NACT (p = 0.0136) were significantly correlated with PFS, whereas age (p = 0.0162) and nodal status after NACT (p = 0.0243) were significantly associated with OS. No significant correlations were found for DTCs or any CTCs before and after therapy with regard to PFS and OS.

CONCLUSIONS

Although CTCs were eradicated more effectively than DTCs, CTCs detected after treatment seemed to be associated with tumor cells showing tumor stem cell characteristics as well as with resistant tumor cell populations that might indicate a worse outcome in the future. Thus, these patients might benefit from additional second-line treatment protocols including bisphosphonates for the eradication of DTCs.

The prognostic impact of soluble and vesicular HLA-G and its relationship to circulating tumor cells in neoadjuvant treated breast cancer patients

The non-classical human leukocyte antigen G (HLA-G) molecule and its soluble forms exert multiple immune suppressive regulatory functions in malignancy and in stem cells contributing to immune escape mechanisms. HLA-G can be secreted as free soluble HLA-G molecules or via extracellular vesicles (EVs). Here we evaluated these soluble HLA-G forms as prognostic marker for prediction of the clinical outcome of neoadjuvant chemotherapy (NACT) treated breast cancer (BC) patients. Plasma samples of BC patients procured before (n=142) and after (n=154) NACT were quantified for total soluble HLA-G (sHLA-Gtot) and HLA-G levels in ExoQuick™ derived EV fractions (sHLA-GEV) by ELISA. The corresponding increments were specified as free sHLA-G (sHLA-Gfree). Total and free sHLA-G were significantly increased in NACT treated BC patients compared to healthy controls (n=16). High sHLA-Gfree levels were exclusively associated to estrogen receptor expression before NACT. Importantly, high sHLA-GEV levels before NACT were related to disease progression and the detection of stem cell-like circulating tumor cells, but high sHLA-Gfree levels indicated an improved clinical outcome. Thus, this study demonstrates for the first time that the different sHLA-G subcomponents represent dissimilar qualitative prognostic impacts on the clinical outcome of NACT treated BC patients, whereas the total sHLA-G levels without separating into subcomponents are not related to clinical outcome.

Photopsias are related in part to perceived stress and positive mood in retinitis pigmentosa

PURPOSE

We measured the relationship between the occurrence of photopsias (spontaneous phosphenes), and retinitis pigmentosa (RP) subjects' level of vision, light exposure, and psychosocial factors to attempt to confirm RP patients' previous reports of these associations.

METHODS

A total of 36 RP subjects self-administered PC-based binocular visual acuity, contrast sensitivity, and visual field tests at home twice a week, for 16 sessions in 2-3 months. After each session, subjects reported photopsias during the vision tests and completed questionnaires: Epworth Sleepiness Scale, Stanford Sleepiness Scale, Perceived Stress Scale, and Positive and Negative Affect Schedules.

RESULTS

Across all subjects, photopsias occurred during 47% of sessions. Five (14%) subjects never noted photopsias, while five others noted photopsias at every session. Two-thirds of subjects experienced photopsias frequently (>20% of sessions). On average, the odds of noticing photopsias increased by 57% for every 1-point increase in mean perceived stress (OR = 1.57; 95% CI: 1.04, 2.4; P = 0.03) or reduced by 38% for every 1-point increase in positive mood (OR=0.62; 95% CI: 0.39, 0.98; P = 0.04), after adjusting for age, gender, and vision. Similarly, the odds of experiencing photopsias during a session increased by 16% for every 3-point increase in perceived stress and decreased by 17% for every 3-point increase in positive mood, after adjusting for age and gender (OR = 1.16; 95% CI: 1.01, 1.33; P = 0.048)(OR = 0.83; 95% CI: 0.73, 0.94; P = 0.004), respectively. Frequency of photopsias was not statistically significantly related to other factors measured.

CONCLUSIONS

Increased photopsias appear to be related to times when subjects report increased perceived stress and/or decreased positive mood, rather than RP patients' age, level of vision, reported light exposure, or sleepiness.

Hormone-induced delayed ovulation affects early embryonic development

OBJECTIVE

To analyze the effects of delayed ovulation on embryonic development in mice, because intrafollicular oocyte development may be delayed during assisted reproductive technology (ART) treatment in humans.

DESIGN

Experimental mouse study.

SETTING

University hospital.

ANIMAL(S)

Female C57Bl/6 mice.

INTERVENTION(S)

Cetrorelix is used as a GnRH-antagonist in ART treatments. To assess the effect of delayed ovulation on embryonic development, cetrorelix was applied concomitantly with follicle stimulation by pregnant mare serum gonadotropin. Ovulation was induced by hCG. Controls were stimulated with pregnant mare serum gonadotropin without delaying ovulation. Suppression of ovulation was assessed from the number of tertiary follicles, ruptured follicles, and corpora lutea in mouse ovaries after cetrorelix treatment. Number and weight of embryos and placentas, as well as number of resorption sites and dead embryos, was determined on day 17.5 of pregnancy.

MAIN OUTCOME MEASURE(S)

Inhibition of ovulation, embryonic development.

RESULT(S)

Cetrorelix inhibited ovulation in mice, as shown by an increase in number of tertiary follicles concomitant with a significant inhibition of follicle rupture and corpora lutea formation. Delayed ovulation caused by Cetrorelix treatment led to a significant increase in resorption sites and a significant decrease in embryonic weight of offspring.

CONCLUSION(S)

Preovulatory oocyte overripeness might have an effect on fertility and embryonic development during ART treatment.

IgM rheumatoid factor elaboration by blood, bone marrow, and synovial mononuclear cells in patients with rheumatoid arthritis

IgM rheumatoid factor (RF) elaboration by rheumatoid arthritis (RA) synovial, bone marrow, and blood mononuclear cells (MNC) is reported. IgM RF was prepared from RF-positive sera by sequential euglobulin precipitation, Sephacryl S300 gel filtration, and IgG-Sepharose affinity chromatography. Purified material, which contained no detectable IgG or IgA, was used in an enzyme-linked immunosorbent assay (ELISA) to quantitate cellular elaboration of IgM RF. Excellent standard curves (r2 = 0.98) were obtained without nonspecific binding of samples or antisera to IgG-coated microtiter plates and without cross-reactivity of standards with antisera other than anti-IgM. We found RA blood MNC (11 patients) spontaneously averaged 15 ng/ml IgM RF (6% of total IgM produced), but elaborated 254 ng/ml IgM RF following pokeweed mitogen (PWM) stimulation (22 patients), exceeding that of 13 normal controls. Bone marrow MNC spontaneously (4 patients) produced 71 ng/ml IgM RF and secreted 78 ng/ml IgM RF with PWM stimulation (9 patients). In contrast synovial fluid MNC (5 patients) spontaneously elaborated 6652 ng/ml IgM RF, significantly (P less than 0.05) more than blood or bone marrow MNC; PWM-stimulated synovial fluid MNC (5 patients) produced 5472 ng/ml IgM RF. These observations confirm selective localization of activated, IgM RF-producing cells to the rheumatoid synovial space.