Estrogen, progesterone, and HER2/neu receptor discordance between primary and metastatic breast tumours-a review

The role of spine stereotactic radiosurgery for patients with breast cancer metastases

PURPOSE

Breast cancer that metastasizes to the spine is associated with low quality of life and poor survival. Radiosurgery has an increasing role in this patient population. This single-institution (2003-2023) study analyzes clinical outcomes and prognostic factors for patients who underwent spinal stereotactic radiosurgery (SSRS) for metastatic breast cancer.

METHODS

Ninety patients (155 unique breast cancer spinal metastases) were treated with SSRS. The median age was 57 years (range: 35-88), and the median KPS was 80 (range: 40-100). Forty-two (27%) lesions were managed surgically prior to radiosurgery. At SSRS, 75 (48%) lesions impinged or compressed the spinal cord per the epidural spinal cord scale (ESCC). Seventy-nine (51%) lesions were categorized as potentially unstable or unstable by the Spinal Instability Neoplastic Score (SINS).

RESULTS

The median follow-up was 15 months (range: 1-183). The median single-session tumor volume was 25.4 cc (range: 2-197), and the median single-fraction prescription dose was 17 Gy (range: 12-25). Seven (5%) lesions locally progressed. The 1-, 2-, and 5-year local control rates were 98%, 97%, and 92%, respectively. The median overall survival (OS) for the cohort was 32 months (range: 2-183). The 1-, 2-, and 5-year OS rates were 72%, 53%, and 30%, respectively. On univariate analysis, KPS ≥ 80 (p = 0.009, HR: 0.51, 95% CI: 0.31-0.84) was associated with improved OS. Patient-reported pain improved (68%), remained stable (29%), or worsened (3%) following radiosurgery. Fifteen (10%) radiation-induced toxicities were reported.

CONCLUSIONS

Spinal radiosurgery is a safe and highly effective long-term treatment modality for metastases to the spine that originate from breast cancer.

Determination of the androgen receptor status of disseminated tumor cells in primary breast cancer patients

PURPOSE

Androgen receptor (AR) can serve as a new therapeutic target since it was shown to play a proliferative role in several breast cancer (BC) subtypes. Moreover, AR positivity has been suggested to reflect the metastatic potential of tumor cells in some BC subtypes. The aim of this study was to determine the AR expression on disseminated tumor cells (DTCs) as a surrogate marker of minimal residual disease (MRD) and potential precursor of metastasis in early BC.

METHODS

Bone marrow (BM) aspirates from 62 DTC-positive early BC patients were included into this study and analyzed by immunofluorescence staining for the presence of AR-positive DTCs. CK-positive, CD45-negative cells containing an intact nucleus (DAPI positive) were identified as DTCs. AR expression of the primary tumor (PT) was assessed by immunohistochemistry on formalin-fixed, paraffin-embedded (FFPE) tumor sections from core biopsies and surgical specimens.

RESULTS

AR status of DTCs could be determined in 21 patients. We detected AR-positive DTCs in nine samples (43%). AR expression of DTCs and corresponding PT showed a concordance rate of 33%. The DTC-AR status did not correlate with clinicopathological factors, nor did we observe a significant correlation between the AR status of the PT and other established prognostic factors for BC.

CONCLUSION

AR-positive DTCs can be detected in BM of early BC patients with a marked discordance of the AR status between DTCs and corresponding PTs. The clinical significance of these findings needs further investigation.

SM, Jacob L, Babu G. Study of Biomarker Discordance between Primary and Recurrent Sites and its Clinical Implications in Metastatic Breast Cancer : A Single Institutional Study from India

S. Shanthala Immunophenotypic discordance of receptors between primary and metastatic sites significantly impacts treatment outcomes. Current international guidelines recommend rebiopsy of accessible metastatic lesions to reassess tissue biomarkers. While existing literature on biomarker changes is conflicting and heterogeneous, similar studies on the Indian cohort of breast cancer patients are lacking. In this context, we aimed to evaluate the frequencies of biomarker changes between biopsies from primary and recurrent sites, and their association with various clinicopathological characteristics, including the type of metastasis and treatment in metastatic breast cancer (MBC) patients. This is an ambispective study performed at a single center. Immunohistochemical (IHC) expression of paired primary and recurrence samples of MBC patients was reviewed for the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 (HER2), and Ki-67. Concordance, loss, and gain of receptors were assessed based on the Allred scores for ER, PR, and HER2. Ki-67 was assessed based on a 14% cutoff. Further, receptor changes were studied in relation to age, menopausal status, morphology, grade, stage, metastatic sites, interval between biopsies, and treatment. At progression, biopsies were obtained from 41.18% of locoregional recurrence and 58.82% of metastatic sites. Despite high discordance of 47% for ER and 68.6% for PR, true receptor conversion was observed in 9.8%, 21.56%, and 5.88% for ER, PR, and HER2, respectively. There was a significant correlation between age and ER discordance ( p  = 0.029). Loss in PR significantly correlated with a gain in Ki-67. Of all the metastatic sites, the lung was significantly associated with PR and Ki-67 concordance ( p  = 0.008 and p  = 0.0425, respectively). Discordance of receptors was neither related to the sites of biopsy (local recurrence or metastatic site) nor to the time interval between biopsies, prior chemotherapy, or hormone therapy. In conclusion, metastatic progression of the disease is accompanied by age-dependent discordance of ER. Unparalleled changes in PR in relation to ER suggest that ER-independent pathways may influence PR expression in MBC. Furthermore, the concurrence of PR loss with Ki-67 gain indicates an aggressive phenotype with disease progression. Hence, follow-up testing of samples for receptor expression is beneficial in determining prognosis and guiding therapeutic decisions.

Expression of Soluble Form of Aurora A as a Predictive Factor for Neoadjuvant Therapy in Breast Cancer Patients: A Single-Center Pilot Study

PURPOSE

To search for new predictive breast cancer biomarkers. We analyzed the serum concentrations of biomarkers involved in carcinogenesis, which can also be targeted by therapy.

METHODS

In a single-center prospective study, the serum levels of Aurora A, thymidine kinase 1, and human epidermal growth factor receptor type 3 (HER3) were determined in 119 women with BC before neoadjuvant treatment using ELISA kits.

RESULTS

The following clinical data were analyzed: age; TNM; the expression of ER, PGR, HER2, and Ki67; histological grade (G); and the response to neoadjuvant treatment (NAT) in the residual tumor burden classification (RCB). A complete pathological response (pCR) was achieved after NAT in 41 patients (34%). The highest proportion of the patients with a confirmed pCR was found for triple negative breast cancer (TNBC) (62.5%); non-luminal HER2-positive (52.6%) cancer subtypes (p = 0.0003); and in the G3 group (50%; p = 0.0078). The patients with higher levels of Aurora A were more likely to achieve pCR (p = 0.039). In the multivariate analysis, the serum Aurora A levels ≥ 4.75 ng/mL correlated with a higher rate of pCR (OR: 3.5; 95% CI: 1.2-10.1; p = 0.023).

CONCLUSIONS

We showed that in a biologically heterogeneous group of BC patients, the pretreatment serum Aurora A levels were of significant value in predicting the response to NAT.

A Radiomics-Based Model for Potentially More Accurate Identification of Subtypes of Breast Cancer Brain Metastases

PURPOSE

Breast cancer brain metastases (BCBM) may involve subtypes that differ from the primary breast cancer lesion. This study aimed to develop a radiomics-based model that utilizes preoperative brain MRI for multiclass classification of BCBM subtypes and to investigate whether the model offers better prediction accuracy than the assumption that primary lesions and their BCBMs would be of the same subtype (non-conversion model) in an external validation set.

MATERIALS AND METHODS

The training and external validation sets each comprised 51 cases (102 cases total). Four machine learning classifiers combined with three feature selection methods were trained on radiomic features and primary lesion subtypes for prediction of the following four subtypes: 1) hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)-, 2) HR+/HER2+, 3) HR-/HER2+, and 4) triple-negative. After training, the performance of the radiomics-based model was compared to that of the non-conversion model in an external validation set using accuracy and F1-macro scores.

RESULTS

The rate of discrepant subtypes between primary lesions and their respective BCBMs were 25.5% (n=13 of 51) in the training set and 23.5% (n=12 of 51) in the external validation set. In the external validation set, the accuracy and F1-macro score of the radiomics-based model were significantly higher than those of the non-conversion model (0.902 vs. 0.765, p=0.004; 0.861 vs. 0.699, p=0.002).

CONCLUSION

Our radiomics-based model represents an incremental advance in the classification of BCBM subtypes, thereby facilitating a more appropriate personalized therapy.

HER2-low breast cancer: evolution of HER2 expression from primary tumor to distant metastases

BACKGROUND

Breast cancer (BC) with low human epidermal growth factor receptor 2 (HER2) expression is attracting much attention due to the breakthrough progress of novel anti-HER2 antibody-drug conjugates. HER2 expression is examined in patients with HER2-low BC and their distant metastases in this study, so as to further clarify the dynamic characteristics of HER2 low status in the process of disease progression.

METHODS

Patients diagnosed with HER2 low breast cancer (defined as IHC1+ or IHC2+/ISH-) between 2012 and 2021 were included in this study. We evaluated HER2 expression of primary sites and metastatic sites, compared the impact of different clinicopathological parameters on HER2 status of metastases and compared the overall survival and disease-free survival of patients with different HER2 status in metastases.

RESULTS

Ninety-eight patients were included. All HER2 IHC scores were confirmed and the consistent rate with the original pathological report was 81.1%. 27.6% of the patients showed different HER2 status in metastases. The HER2 discordance rate differed among different metastatic sites (p = 0.040). The higher the T stage of the primary BC, the higher the rate of HER2 discordance was observed (p = 0.042). For the specimen type of metastasis, HER2 discordant rate was higher in surgical specimen than biopsy (p = 0.050). No difference of HER2 discordance rate was found between HER2-1+ and HER2-2+ patients. But comparing HER2 IHC score, HER2-2+ patients were less likely to have consistent metastatic HER2 levels than HER2-1+ patients (p = 0.006). No difference in survival outcomes was observed between patients with different HER2 status in metastases.

CONCLUSIONS

There is a possibility of HER2 expression alteration in the metastases of HER2-low breast cancer. And the rate of altered HER2 low expression was different among different metastatic sites, different T stages of primary BC and specimen type of metastasis. No prognostic significance was observed.

Discordances in expression of human epidermal growth factor receptor 2 between primary and metastatic uterine carcinosarcoma: A proposal for HER2-targeted therapy specimen selection

Uterine carcinosarcoma (UCS) frequently expresses human epidermal growth factor receptor 2 (HER2) and metastasizes. However, little is known about changes in the HER2 expression status in metastatic lesions and its impact on clinical outcomes. In 41 patients with synchronous or metachronous metastases and matched primary UCSs, we assessed the HER-2 expression using immunohistochemistry and scored it per the 2016 American Society of Clinical Oncology/College of American Pathologists guidelines, modified for UCS. We compared HER2 scores between paired primary and metastatic lesions and reviewed the association between clinicopathological characteristics and impact on overall survival. HER2 scores of 3+, 2+, 1+, and 0 were observed in 12.2 %, 34.2 %, 26.8 %, and 26.8 % of primary tumors, respectively, and 9.8 %, 19.5 %, 43.9 %, and 26.8 % of metastatic tumors, respectively. HER2 intratumoral heterogeneity occurred in 46.3 % and 19.5 % of the primary and metastatic lesions, respectively. The agreement rate of the HER2 score was 34.2 % in the four-tiered scale, while it was 70.7 % in the two-tiered scale (score 0 vs. score ≥ 1+) with fair agreement (к = 0.26). Patients with HER2 discordance showed significantly shorter overall survival (hazard ratios = 2.38, 95 % confidence interval 1.01-5.5, p = 0.049). HER2 discordance was not associated with specific clinicopathological characteristics. Discordance in HER2 status between primary and metastatic tumors in UCS was frequently observed regardless of clinicopathological characteristics and was a poor prognostic factor. Even if one tumor (primary or metastatic) is HER2 negative, HER2 testing of other tumors may be beneficial in terms of patient treatment options.

Evolution of biological features of invasive lobular breast cancer: comparison between primary tumor and metastases

BACKGROUND

Invasive lobular carcinoma (ILC) has unique clinical-biological features. Phenotypical differences between primary tumours (PTs) and metastases (M) have been described for invasive ductal carcinoma, but data on ILC are limited.

METHODS

We retrospectively analysed patients with recurrent ILC from our institution from 2013 to 2020. We evaluated the discordance of the oestrogen receptor (ER), progesterone receptor (PgR) and HER2 between PT and M, to understand prognostic and therapeutic implications.

RESULTS

Thirteen percent (n = 91) of all patients had ILC. We observed 15%, 44% and 5% of ER, PgR and HER2 status discordance between PT and M. ER/PgR discordance was related to receptor loss and HER2 mainly due to gain. PT presented a luminal-like phenotype (93%); 6% and 1% were triple-negative (TNBC) and HER2-positive. In M, there was an increase in TNBC (16%) and HER2-positive (5%). Metastasis-free survival and overall survival (OS) were different according to clinical phenotype, with poorer prognosis for HER2+ and TNBC (p < 0.001); OS after metastatic progression did not differ across phenotypes (p = 0.079). In luminal-like ILC (n = 85) at diagnosis, we found that OS after relapse was poorer in patients experiencing a phenotype switch to TNBC but improved in patients with HER2 gain (p = 0.0028). Poorer survival was reported in patients with a PgR and/or ER expression loss of ≥25%. There was HER2-low enrichment in M1 (from 37% to 58%): this change was not associated with OS (p > 0.05).

CONCLUSION

Our results suggest that phenotype switch after metastatic progression may be associated with patients' outcomes. Tumour biopsy in recurrent ILC could drive treatment decision-making, with prognostic implications.

Distribution, dynamic evolution, and clinical outcomes of patients with advanced breast cancer according to HER2 expression

BACKGROUND

Novel antibody‒drug conjugates (ADC) have shown great efficacy in HER2-low advanced breast cancer. However, the clinical features of HER2-low disease still need to be clarified. The current study aims to evaluate the distribution and dynamic change in HER2 expression in patients with disease recurrence and the clinical outcome of those patients.

METHODS

Patients with pathologically diagnosed relapsed breast cancer between 2009 and 2018 were included. Samples were considered HER2-zero when the immunohistochemistry (IHC) score was 0, HER2-low when the IHC score was 1 + or 2 + with negative fluorescence in situ hybridization (FISH) results, and HER2-positive when the IHC score was 3 + or the FISH results were positive. Breast cancer-specific survival (BCSS) was compared among the three HER2 groups. Changes in HER2 status were also evaluated.

RESULTS

A total of 247 patients were included. Among recurrent tumors, 53 (21.5%) were HER2-zero, 127 (51.4%) were HER2-low, and 67 (27.1%) were HER2-positive. The HER2-low subtype represented 68.1% of the HR-positive breast cancer group and 31.3% of the HR-negative group (P < 0.001). This three-group classification of HER2 status was prognostic in advanced breast cancer (P = 0.0011), with HER2-positive patients having the best clinical outcome after disease recurrence (P = 0.024), while only marginal survival advantages were observed in HER2-low patients versus HER2-zero patients (P = 0.051). In the subgroup analysis, the survival difference was observed only in patients with HR-negative recurrent tumors (P = 0.0006) or with distant metastasis (P = 0.0037). The overall discordance rate of HER2 status between primary and recurrent tumors was 38.1%, with 25 (49.0%) primary HER2-zero patients and 19 (26.8%) HER2-positive patients shifting to HER2-low at recurrence.

CONCLUSION

Nearly half of the advanced breast cancer patients had HER2-low disease, which indicates a poorer prognosis than HER2-positive disease and marginally better outcomes than HER2-zero disease. During disease progression, one-fifth of tumors convert to HER2-low entities, and the corresponding patients may benefit from ADC treatment.

Case report: Response to endocrine therapy in triple-negative breast cancer metastases with altered hormone receptors

Triple-negative breast cancer refers to breast cancer patients with negative estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER2). Metastatic triple-negative breast cancer is predominantly treated with chemotherapy, but later-line treatment remains challenging. Breast cancer is highly heterogeneous, and the expression of hormone receptors is often inconsistent between primary and metastatic lesions. Here, we report a case of triple-negative breast cancer 17 years after surgery with lung metastases for 5 years that progressed to pleural metastases after multiple lines of chemotherapy. The pleural pathology suggested ER (+) and PR (+) and transformation to luminal A breast cancer. This patient received fifth-line letrozole endocrine therapy and achieved partial response (PR). The patient's cough and chest tightness improved after treatment, associated tumor markers decreased, and progression-free survival (PFS) exceeded 10 months. Our results may be of clinical relevance for patients with hormone receptor alterations in advanced triple-negative breast cancer and suggest that individualized regimens should be developed for breast cancer based on the molecular expression of tumor tissue at the primary and metastatic sites.

Breast cancer heterogeneity and its implication in personalized precision therapy

Breast cancer heterogeneity determines cancer progression, treatment effects, and prognosis. However, the precise mechanism for this heterogeneity remains unknown owing to its complexity. Here, we summarize the origins of breast cancer heterogeneity and its influence on disease progression, recurrence, and therapeutic resistance. We review the possible mechanisms of heterogeneity and the research methods used to analyze it. We also highlight the importance of cell interactions for the origins of breast cancer heterogeneity, which can be further categorized into cooperative and competitive interactions. Finally, we provide new insights into precise individual treatments based on heterogeneity.

Famine Exposure during Early Life and Risk of Cancer in Adulthood: A Systematic Review and Meta-Analysis

OBJECTIVES

Emerging evidences have explored the association between famine exposure during early life and cancer risk in adulthood, but the results remain controversial and inconsistent. This study aimed to provide a comprehensive evidence on the relation of famine exposure to later cancer risk.

DESIGN

Systematic review and meta-analysis.

METHODS

Relevant reports published up to March, 2022 were identified by searching PubMed, Embase, Web of sciences and Medline databases. Pooled relative ratios (RRs) with 95% confidence intervals (CIs) were used to evaluate the effect famine exposure on cancer risk.

RESULTS

Totally, 18 published articles with 6,061,147 subjects were included in this study. Compared with unexposed group, early life famine exposure dramatically increased the risk of cancer in adulthood (RR=1.13, 95% CI: 1.04-1.22). The pooled RRs were different in terms of sex, exposure severity, exposure period, famine type, study design type and cancer location. A remarkably elevated risk for cancer was discerned in women exposed to famine (RR=1.09, 95% CI: 1.00-1.18), severe exposure (RR=1.12, 95% CI: 1.02-1.22) and adolescence exposure (RR=1.76, 95% CI: 1.02-2.50), Chinese famine exposure (RR=1.55, 95% CI: 1.29-1.82) and cohort studies (RR=1.28, 95% CI: 1.13-1.42). Moreover, a significant association of early-life famine exposure with increased risk of breast (RR=1.16, 95% CI: 1.05-1.27) and stomach cancers (RR=1.89, 95% CI: 1.24-2.54) was observed.

CONCLUSION

This meta-analysis suggests that exposure to famine during early life may increase the risk of cancer in adulthood. The above-mentioned association is pronounced in women exposed to famine, severe exposure, adolescence exposure, Chinese famine, cohort studies, breast and stomach cancers. It is essential for decision-makers to take targeted measures for improving population awareness regarding the long-term effect of early life nutritional status.

Multiple receptor conversions during the course of metastatic breast cancer therapy: a case report and review of the literature

BACKGROUND

Adjuvant systemic therapy decreases recurrence and death from breast cancer, but late relapse still occurs. Therapeutic decisions are based heavily on receptor tissue characterization. Even though the vast majority of metastatic sites do not have receptor conversions, they can occur at the time of metastasis and/or during the course of treatment. However, multiple receptor conversions are uncommon.

CASE PRESENTATION

We present an unusual case of a Caucasian patient originally diagnosed with an estrogen receptor-positive, progesterone receptor-positive, and human epidermal growth factor receptor 2-negative primary breast cancer who had a recurrence after 15 years of therapy. Her metastatic tumor had a different receptor status than the original tumor. During the course of therapy, at the time of progression, a new biopsy showed that her tumor had changed once more.

CONCLUSION/DISCUSSION

Tracking receptor conversions is important in metastatic breast cancer treatment. Single receptor conversions have been documented to occur, but not much is known of multiple receptor conversions. This case sheds light on the possibility of patients having multiple receptor conversions and the importance of performing multiple biopsies during the course of metastatic treatment.

Bone Metastasis of Breast Cancer: Molecular Mechanisms and Therapeutic Strategies

Bone metastasis is a common complication of many types of advanced cancer, including breast cancer. Bone metastasis may cause severe pain, fractures, and hypercalcemia, rendering clinical management challenging and substantially reducing the quality of life and overall survival (OS) time of breast cancer patients. Studies have revealed that bone metastasis is related to interactions between tumor cells and the bone microenvironment, and involves complex molecular biological mechanisms, including colonization, osteolytic destruction, and an immunosuppressive bone microenvironment. Agents inhibiting bone metastasis (such as bisphosphate and denosumab) alleviate bone destruction and improve the quality of life of breast cancer patients with bone metastasis. However, the prognosis of these patients remains poor, and the specific biological mechanism of bone metastasis is incompletely understood. Additional basic and clinical studies are urgently needed, to further explore the mechanism of bone metastasis and develop new therapeutic drugs. This review presents a summary of the molecular mechanisms and therapeutic strategies of bone metastasis of breast cancer, aiming to improve the quality of life and prognosis of breast cancer patients and provide a reference for future research directions.

Estimation of Epidermal growth factor (EGF), HER2, CA15-3 and Acid phosphatase in Iraqi breast cancer women

Breast cancer is one of frequent cancer that affects millions of people worldwide. Delayed diagnosis of these cancers has raised mortality and morbidity. Cancer biomarkers have tremendously increased the efficacy of treatment and the effectiveness of detection. This study aimed to investigate some biomarkers, including EGF, HER2, CA15-3, and Acid phosphatase, associated with early breast cancer (BC) diagnosis in Iraqi women. Carried on 90 Samples, the patients attended the Center for Early Detection of Breast Tumor at an oncology teaching hospital in Medical City. The study was conducted between 15/February (2021) and 20/July (2021). The consultant medical personnel made the diagnosis based on a Triple Assessment Technique, including physical breast examination, ultrasonography, with or without mammography and fine needle aspiration cytology. Female patients were divided into three groups (Benign, malignant and control). Benign B(34 patients) was split into subgroups, including. Benign premenopausal group B1(17 patients) Benign post-menopausal group B2(17patients) and malignant M(34 patients), malignant premenopausal group M1(17 patients) and malignant post-menopausal group M2(17 patients), and control group C include (11) premenopausal stage C1and (11) post-menopausal group C2. The value of EGF in Malignant cancer M1 (179.80 ±19.07) and M2(130.59 ±18.59)shows a highly significant (P≤0>05) increase in comparison with benign cancer and B2 and healthy control C1and C2 groups, respectively but B1 and B2 shows high significant (P≤0>05)decrease in comparison with C1 and C2 respectively. The values of HER2 show in B2(1.377±0.10); M1(11.76±0.10), and M2(11.79±0.09) increased significantly(P≤0.05) in comparison with C1, C2, B1 respectively. The values of CA-15-3 in M1 and M2 increase significantly(P≤0.05) compared with C1, C2, B1, and B2. The values of acid phosphatase in pre-and post-menopausal males in M1 and M2 increased significantly (p<0.05) compared with C1andC2. Keywords: Epidermal growth factor, breast cancer, Acid phosphatase, HER2, CA15-3

Temporal Heterogeneity of HER2 Expression and Spatial Heterogeneity of 18F-FDG Uptake Predicts Treatment Outcome of Pyrotinib in Patients with HER2-Positive Metastatic Breast Cancer

Background: This study aimed to evaluate tumor heterogeneity of metastatic breast cancer (MBC) and investigate its impact on the efficacy of pyrotinib in patients with HER2-positive MBC. Methods: MBC patients who underwent 18F-FDG PET/CT before pyrotinib treatment were included. Temporal and spatial tumor heterogeneity was evaluated by the discordance between primary and metastatic immunohistochemistry (IHC) results and baseline 18F-FDG uptake heterogeneity (intertumoral and intratumoral heterogeneity indexes: HI-inter and HI-intra), respectively. Progression-free survival (PFS) was estimated by the Kaplan−Meier method and compared by a log-rank test. Results: A total of 572 patients were screened and 51 patients were included. In 36 patients with matched IHC results, 25% of them had HER2 status conversion. Patients with homogenous HER2 positivity had the longest PFS, followed by patients with gained HER2 positivity, while patients with HER2 negative conversion could not benefit from pyrotinib (16.8 vs. 13.7 vs. 3.6 months, p < 0.0001). In terms of spatial heterogeneity, patients with high HI-intra and HI-inter had significantly worse PFS compared to those with low heterogeneity (10.6 vs. 25.3 months, p = 0.023; 11.2 vs. 25.3 months, p = 0.040). Conclusions: Temporal heterogeneity of HER2 status and spatial heterogeneity of 18F-FDG uptake could predict the treatment outcome of pyrotinib in patients with HER2-positive MBC, which provide practically applicable methods to assess tumor heterogeneity and guidance for treatment decisions.

Radiomic Signatures for Predicting Receptor Status in Breast Cancer Brain Metastases

Backgrounds

A significant proportion of breast cancer patients showed receptor discordance between primary cancers and breast cancer brain metastases (BCBM), which significantly affected therapeutic decision-making. But it was not always feasible to obtain BCBM tissues. The aim of the present study was to analyze the receptor status of primary breast cancer and matched brain metastases and establish radiomic signatures to predict the receptor status of BCBM.

Methods

The receptor status of 80 matched primary breast cancers and resected brain metastases were retrospectively analyzed. Radiomic features were extracted using preoperative brain MRI (contrast-enhanced T1-weighted imaging, T2-weighted imaging, T2 fluid-attenuated inversion recovery, and combinations of these sequences) collected from 68 patients (45 and 23 for training and test sets, respectively) with BCBM excision. Using least absolute shrinkage selection operator and logistic regression model, the machine learning-based radiomic signatures were constructed to predict the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status of BCBM.

Results

Discordance between the primary cancer and BCBM was found in 51.3% of patients, with 27.5%, 27.5%, and 5.0% discordance for ER, PR, and HER2, respectively. Loss of receptor expression was more common (33.8%) than gain (18.8%). The radiomic signatures built using combination sequences had the best performance in the training and test sets. The combination model yielded AUCs of 0.89, 0.88, and 0.87, classification sensitivities of 71.4%, 90%, and 87.5%, specificities of 81.2%, 76.9%, and 71.4%, and accuracies of 78.3%, 82.6%, and 82.6% for ER, PR, and HER2, respectively, in the test set.

Conclusions

Receptor conversion in BCBM was common, and radiomic signatures show potential for noninvasively predicting BCBM receptor status.

Diagnostic and Prognostic Role of 18F-Fluoroestradiol PET in Metastatic Breast Cancer: The Second Youth of an Older Theranostic Concept

Since the discovery of the role of female hormones in breast cancer (BC) pathophysiology, in vivo detection of oestrogen receptor (ER) distribution has been one of the major goals of nuclear medicine and molecular imaging [...]

Loss of human epidermal receptor-2 in human epidermal receptor-2+ breast cancer after neoadjuvant treatment: A case report

BACKGROUND

Human epidermal receptor-2 (HER-2) expression has been reported to be discordant between primary tumor and metastatic tissue.

CASE SUMMARY

We presented a case diagnosed with the HER-2+ breast cancer patient who exhibited changes in the expression of HER-2 receptors on tumour samples from surgical specimens obtained after neoadjuvant treatment (NAT) compared with initial biopsy. The patient underwent a HER-2-targeted therapy consequently, in spite of HER+ gene loss. After the surgery, the patient subsequently underwent endocrine therapy and radiotherapy.

CONCLUSION

Changes in HER-2 expression after NAT should be retested by physicians and pathologists before systemic treatment instead of avoiding further HER-2-targeted therapy, and we will perform immunohistochemical multiple-spot biopsy analyses of other important clinical issues to better define prognosis and tailor subsequent adjuvant therapy.

Single HER2-positive tumor cells are detected in initially HER2-negative breast carcinomas using the DEPArray™-HER2-FISH workflow

Background

In breast cancer (BC), overexpression of HER2 on the primary tumor (PT) is determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to stratify samples as negative, equivocal and positive to identify patients (pts) for anti-HER2 therapy. CAP/ASCO guidelines recommend FISH for analyzing HER2/neu (ERBB2) gene amplification and for resolving equivocal HER2 IHC results. However, pre-analytical and analytical aspects are often confounded by sample related limitations and tumor heterogeneity and HER2 expression may differ between the PT and circulating tumor cells (CTCs), the precursors of metastasis. We used a validation cohort of BC patients to establish a new DEPArray™-PT-HER2-FISH workflow for further application in a development cohort, characterized as PT-HER2-negative but CTC-HER2/neu-positive, to identify patients with PT-HER2 amplified cells not detected by routine pathology.

Methods

50 µm FFPE tumor curls from the validation cohort (n = 49) and the development cohort (n = 25) underwent cutting, deparaffinization and antigen retrieval followed by dissociation into a single-cell suspension. After staining for cytokeratin, vimentin, DAPI and separation via DEPArray™, single cells were processed for HER2-FISH analysis to assess the number of chromosome 17 and HER2 loci signals for comparison, either with available IHC or conventional tissue section FISH. CTC-HER2/neu status was determined using the AdnaTest BreastCancer (QIAGEN, Hilden, Germany).

Results

Applying CAP/ASCO guidelines for HER2 evaluation of single PT cells, the comparison of routine pathology and DEPArray™-HER2-FISH analysis resulted in a concordance rate of 81.6% (40/49 pts) in the validation cohort and 84% (21/25 pts) in the development cohort, respectively. In the latter one, 4/25 patients had single HER2-positive tumor cells with 2/25 BC patients proven to be HER2-positive, despite being HER2-negative in routine pathology. The two other patients showed an equivocal HER2 status in the DEPArray™-HER2-FISH workflow but a negative result in routine pathology. Whereas all four patients with discordant HER2 results had already died, 17/21 patients with concordant HER2 results are still alive.

Conclusions

The DEPArray™ system allows pure tumor cell recovery for subsequent HER2/neu FISH analysis and is highly concordant with conventional pathology. For PT-HER2-negative patients, harboring HER2/neu-positive CTCs, this approach might allow caregivers to more effectively offer anti-HER2 treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-022-01330-8.

Discordance of PIK3CA and TP53 mutations between breast cancer brain metastases and matched primary tumors

There is limited knowledge of the biology of breast cancer (BC) brain metastasis (BM). We primarily aimed to determine the mutations in BCBM and to compare the mutational pattern with the matched primary breast cancer (BC). Secondary aims were to determine mutations in each subgroup (Luminal A-/B-like, HER2+ and TNBC) of BCBM, and to determine survival according to specific mutations. We investigated 57 BCBMs, including 46 cases with matched primary tumors (PT) by targeted Next Generation Sequencing (NGS) using the Cancer Hotspot Panel v2 (ThermoFisher Scientific) covering 207 targeted regions in 50 cancer related genes. Subtype according to immunohistochemistry was re-evaluated. NGS results fulfilling sequencing quality criteria were obtained from 52 BM and 41 PT, out of which 37 were matched pairs. Pathogenic mutations were detected in 66% of PTs (27/41), and 62% of BMs (32/52). TP53 mutations were most frequent; 49% (20/41) of PTs and 48% (25/52) in BMs, followed by PIK3CA mutations; 22% (9/42) in PTs and 25% (13/52) in BMs. Mutations in CDH1, EGFR, HRAS, RB1 CDKN2A and PTEN were detected in single pairs or single samples. Mutational pattern was discordant in 24% of matched pairs. We show a discordance of PIK3CA and TP53 mutations of roughly 25% indicating the need to develop methods to assess mutational status in brain metastasis where analysis of cell-free DNA from cerebrospinal fluid (CSF) has shown promising results.

HRAS is a therapeutic target in malignant chemo-resistant adenomyoepithelioma of the breast

Malignant adenomyoepithelioma (AME) of the breast is an exceptionally rare form of breast cancer, with a significant metastatic potential. Chemotherapy has been used in the management of advanced AME patients, however the majority of treatments are not effective. Recent studies report recurrent mutations in the HRAS Q61 hotspot in small series of AMEs, but there are no preclinical or clinical data showing H-Ras protein as a potential therapeutic target in malignant AMEs. We performed targeted sequencing of tumours’ samples from new series of 13 AMEs, including 9 benign and 4 malignant forms. Samples from the breast tumour and the matched axillary metastasis of one malignant HRAS mutated AME were engrafted and two patient-derived xenografts (PDX) were established that reproduced the typical AME morphology. The metastasis-derived PDX was treated in vivo by different chemotherapies and a combination of MEK and BRAF inhibitors (trametinib and dabrafenib). All malignant AMEs presented a recurrent mutation in the HRAS G13R or G12S hotspot. Mutation of PIK3CA were found in both benign and malignant AMEs, while AKT1 mutations were restricted to benign AMEs. Treatment of the PDX by the MEK inhibitor trametinib, resulted in a marked anti-tumor activity, in contrast to the BRAF inhibitor and the different chemotherapies that were ineffective. Overall, these findings further expand on the genetic features of AMEs and suggest that patients carrying advanced HRAS-mutated AMEs could potentially be treated with MEK inhibitors.

Development of a 99mTc-Labeled Single-Domain Antibody for SPECT/CT Assessment of HER2 Expression in Breast Cancer

Accurate determination of human epidermal growth factor receptor 2 (HER2) expression is essential for HER2-targeted therapy in patients with cancer. HER2 expression in a complex environment, such as in a heterogeneous tumor, makes the precise assessment of the HER2 status difficult using current methods. In this study, we developed a novel ^99mTc-labeled anti-HER2 single-domain antibody (^99mTc-NM-02) as a molecular imaging tracer for the noninvasive detection of HER2 expression and investigated its safety, radiation dosimetry, biodistribution, and tumor-targeting potential in 10 patients with breast cancer. Our data showed that no drug-related adverse reactions occurred. The tracer mainly accumulated in the kidneys and liver with mild uptake in the spleen, intestines, and thyroid; however, only background tracer levels were observed in other organs where primary tumors and metastases typically occurred. The mean effective dose was 6.56 × 10^-3 mSv/MBq, and tracer uptake was visually observed in the primary tumors and metastases. A maximal standard uptake value of 1.5 was determined as a reasonable cutoff for identifying HER2 positivity using SPECT/CT imaging. Our ^99mTc-NM-02 tracer is safe for use in breast cancer imaging, with reasonable radiation doses, favorable biodistribution, and imaging characteristics. ^99mTc-NM-02 SPECT imaging may be an accurate and noninvasive method to detect the HER2 status in patients with breast cancer.

The prognostic relevance of HER2-positivity gain in metastatic breast cancer in the ChangeHER trial

In metastatic breast cancer (mBC), the change of human epidermal growth factor receptor 2 (HER2) status between primary and metastatic lesions is widely recognized, however clinical implications are unknown. Our study address the question if relevant differences exist between subjects who preserve the HER2 status and those who gain the HER2 positivity when relapsed. Data of patients affected by HER2-positive mBC, treated with pertuzumab and/or trastuzumab-emtansine (T-DM1) in a real-world setting at 45 Italian cancer centers were retrospectively collected and analyzed. From 2003 to 2017, 491 HER2‐positive mBC patients were included. Of these, 102 (20.7%) had been initially diagnosed as HER2-negative early BC. Estrogen and/or progesterone receptor were more expressed in patients with HER2-discordance compared to patients with HER2-concordant status (p < 0.0001 and p = 0.006, respectively). HER2-discordant tumors were characterized also by a lower rate of brain metastases (p = 0.01) and a longer disease free interval (p < 0.0001). Median overall survival was longer, although not statistically significant, in the subgroup of patients with HER2-discordant cancer with respect to patients with HER2-concordant status (140 vs 78 months, p = 0.07). Our findings suggest that patients with HER2-positive mBC with discordant HER2 status in early BC may have different clinical, biological and prognostic behavior compared to HER2-concordant patients.

Association of Biomarker Discrepancy and Treatment Decision, Disease Outcome in Recurrent/Metastatic Breast Cancer Patients

Background

Biomarker discrepancy between primary and recurrent/metastatic breast cancer is well known, however its impact on prognosis and treatment after relapse is still unclear. Current study aims to evaluate biomarkers discrepancy between primary and recurrent/metastatic lesions as well as to investigate its association with following treatment pattern and disease outcome.

Patients and methods

We retrospectively included consecutive breast cancer patients undergoing surgery in our center from Jan. 2009 to Dec. 2016 and reported disease recurrence. Patients with re-biopsy and paired biomarkers statuses on primary and recurrent/metastatic lesions were further analyzed. Kappa test was used to analyze the concordance rate of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) status. Post-recurrence survival (PRS) was compared between subgroups by Kaplan-Meier curve. Cox regression model was applied to identify impact factors for PRS.

Results

A total of 156 patients were finally included, of whom 70 and 86 had loco-regional and distant recurrence, respectively. Concordance rates of ER, PR and HER2 were 83.3%, 66.7%, and 97.1%, respectively, which was similarly distributed among different recurrent sites (all P > 0.05). Primary ER-positivity (vs ER-negativity, P = 0.014) and loco-regional recurrence (vs distant metastasis, P = 0.001) were independently associated with superior PRS, while patients with visceral metastasis (P < 0.001) had the worst disease outcome. Hormone receptor/HER2 status discrepancy was observed in 28 patients. Fifteen of them changed systemic treatment based on biomarker statuses of recurrent lesion, however, their PRS was not improved compared to those 13 patients who continued the same treatment according to primary biomarkers statuses (P = 0.298).

Conclusion

Biomarker discrepancy was observed between primary and recurrent/metastatic breast cancer lesions and had certain influence on treatment strategies after relapse. However, its impact on disease outcome wasn’t established in the current study, which deserves further evaluation.

Inter-Metastatic Heterogeneity of Tumor Marker Expression and Microenvironment Architecture in a Preclinical Cancer Model

BACKGROUND

Preclinical drug development studies rarely consider the impact of a candidate drug on established metastatic disease. This may explain why agents that are successful in subcutaneous and even orthotopic preclinical models often fail to demonstrate efficacy in clinical trials. It is reasonable to anticipate that sites of metastasis will be phenotypically unique, as each tumor will have evolved heterogeneously with respect to gene expression as well as the associated phenotypic outcome of that expression. The objective for the studies described here was to gain an understanding of the tumor heterogeneity that exists in established metastatic disease and use this information to define a preclinical model that is more predictive of treatment outcome when testing novel drug candidates clinically.

METHODS

Female NCr nude mice were inoculated with fluorescent (mKate), Her2/neu-positive human breast cancer cells (JIMT-mKate), either in the mammary fat pad (orthotopic; OT) to replicate a primary tumor, or directly into the left ventricle (intracardiac; IC), where cells eventually localize in multiple sites to create a model of established metastasis. Tumor development was monitored by in vivo fluorescence imaging (IVFI). Subsequently, animals were sacrificed, and tumor tissues were isolated and imaged ex vivo. Tumors within organ tissues were further analyzed via multiplex immunohistochemistry (mIHC) for Her2/neu expression, blood vessels (CD31), as well as a nuclear marker (Hoechst) and fluorescence (mKate) expressed by the tumor cells.

RESULTS

Following IC injection, JIMT-1mKate cells consistently formed tumors in the lung, liver, brain, kidney, ovaries, and adrenal glands. Disseminated tumors were highly variable when assessing vessel density (CD31) and tumor marker expression (mkate, Her2/neu). Interestingly, tumors which developed within an organ did not adopt a vessel microarchitecture that mimicked the organ where growth occurred, nor did the vessel microarchitecture appear comparable to the primary tumor. Rather, metastatic lesions showed considerable variability, suggesting that each secondary tumor is a distinct disease entity from a microenvironmental perspective.

CONCLUSIONS

The data indicate that more phenotypic heterogeneity in the tumor microenvironment exists in models of metastatic disease than has been previously appreciated, and this heterogeneity may better reflect the metastatic cancer in patients typically enrolled in early-stage Phase I/II clinical trials. Similar to the suggestion of others in the past, the use of models of established metastasis preclinically should be required as part of the anticancer drug candidate development process, and this may be particularly important for targeted therapeutics and/or nanotherapeutics.

Heterogeneity of bone metastases as an important prognostic factor in patients affected by oestrogen receptor-positive breast cancer. The role of combined [18F]Fluoroestradiol PET/CT and [18F]Fluorodeoxyglucose PET/CT

PURPOSE

To assess the prognostic role of different inter and intralesional expression (heterogeneity) of oestrogen receptor (ER) in bone metastases, as identified by the combined use of [18F]FES PET/CT and [18F]FDG PET/CT in patients with oestrogen receptor-positive (ER+) metastatic breast cancer (BC).

METHODS

We analysed patients with a new diagnosis of bone metastases who were candidates for first-line systemic endocrine therapy. Before starting therapy, patients underwent baseline [18F]FES PET/CT and [18]FDG PET/CT. Semi-quantitative evaluation of whole-body bone metabolic burden (WB-B-MB) was performed on [18F]FES and [18F]FDG PET/CT in order to evaluate disease extent, tumour metabolism and ER heterogeneity. We used time-to-event analyses (Kaplan-Meier and Cox proportional-hazards methods) to estimate progression-free (PFS) and overall survival (OS), in order to assess the independent prognostic value of [18F]FES PET/CT and [18F]FDG PET/CT, alone and in combination.

RESULTS

According to our criteria, we enrolled 49 patients. Over a median follow-up of 44.7 months, 35 patients suffered disease progression (71.4 %) and 15 died of disease (30.6 %). When the risk of disease progression was calculated by means of the Cox model, only [18F]FDG WB-B-MB was independently and directly associated to PFS (p = 0.02). On analysing the association between all prognostic parameters and survival, the Cox model showed that the only parameter associated with OS was the WB-B-MB FES/FDG ratio (p = 0.01).

CONCLUSION

The combined use of [18F]FES-PET/CT and [18F]FDG-PET/CT can identify ER heterogeneity in BC bone metastases. This heterogeneity is significantly associated with survival. Moreover, the extension of the FDG-avid component correlates with the risk of disease progression.

Bone biopsy results in patients with a history of malignancy: a case series of 378 patients

OBJECTIVE

The value of a bone biopsy in patients who present with a bone lesion and past medical history of malignancy is uncertain. The objective of this study was to evaluate the outcome of bone biopsies in patients with a history of a malignancy undergoing bone biopsy of a lesion in a regional bone tumour unit. Secondary outcomes include the assessment of survival in the different outcome groups.

MATERIALS AND METHODS

This was a retrospective study of patients, with a previous malignancy and suspicious bone lesions, who underwent bone biopsy for final diagnosis between March 2010 and September 2019. Results of the biopsy were summarized into 3 groups: confirmed original malignancy, confirmed benign diagnosis, and confirmed new malignancy. Survival analysis of each group was also undertaken.

RESULTS

A total of 378 patients met the inclusion criteria (mean age 64 years, 216 females (57%)). In 250 cases (66%), the original malignancy was confirmed on the bone biopsy; in 128 cases, an alternative diagnosis was confirmed (benign diagnosis in 69 (18%)), and 59 had a new malignancy (16%). Survival was significantly greater for those in whom a benign diagnosis was confirmed (logrank test p = 0.0100).

CONCLUSION

This study shows that for patients presenting with a suspicious bone lesion, together with a history of malignancy, in a third of cases, the bone biopsy will confirm an alternative diagnosis of a benign lesion or a new malignancy. Survival of these patients will vary significantly depending on the biopsy outcome.

Discordance in ER, PR, HER2, and Ki-67 Expression Between Primary and Recurrent/Metastatic Lesions in Patients with Primary Early Stage Breast Cancer and the Clinical Significance: Retrospective Analysis of 75 Cases

Background: The objective was to explore the discordance in the expression of the estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 between primary and recurrent/metastatic lesions in patients with early stage breast cancer as well as the prognostic impact.

Method: Patients with early-stage primary breast cancer and confirmed recurrence/metastasis at Peking Union Medical College Hospital between January 2005 and August 2018 were screened. The details of discordance in each parameter between primary and recurrent/metastatic lesions and progression were recorded. Regression and survival analysis were applied to determine the association and clinical impact of the discordance.

Results: We evaluated 75 patients. The discordance rate of ER, PR, HER2, and Ki-67 expression was 9.3, 14.7, 14.7, and 21.5%, respectively. Additionally, 66.7, 11.8, 14.3, and 0% of patients with Luminal A, Luminal B, HER2, and triple-negative primary tumors presented with a different subtype for the recurrent/metastatic tumors, respectively. No statistical difference in progression-free survival was observed according to the subtype of the recurrent or metastatic breast cancer (p > 0.05). Among 69 patients for whom treatment was adjusted after recurrence or metastasis, 66 patients remained recurrence-free during the follow-up period.

Conclusion: For patients with early-stage breast cancer, the ER, PR, HER2, and Ki-67 expression profile for recurrent/metastatic tumors does not always match that of the primary tumor. After adjusting treatment according to the receptor expression in recurrent/metastatic lesions, most patients remained progression-free during the follow-up period.

Neoadjuvant Chemotherapy in Breast Cancer: Review of the Evidence and Conditions That Facilitated Its Use during the Global Pandemic

Practice and behaviour change in healthcare is complex, and requires a set of critical steps that would be needed to implement and sustain the change. Neoadjuvant chemotherapy for breast cancer is traditionally used for locally advanced disease and is primarily advantageous for surgical downstaging purposes. However, it does also offer patients with certain biologic subtypes such as the triple negative or Her2 positive breast cancers the opportunity to improve survival, even in early stage disease. During the height of the pandemic, an opportunity and motivation for the increased use of neoadjuvant therapy in breast cancer was identified. This paper describes the conditions that have supported this practice change at the provider and institutional levels. We also include our own institutional algorithm based on tumor biology and extent of disease that have guided our decisions on breast cancer management during the pandemic. Our processes can be adapted by other institutions and breast oncology practices in accordance with local conditions and resources, during and beyond the pandemic.

Can we cure oligometastatic disease? A practical point of view

PURPOSE OF REVIEW

To critically analyze the available evidence on oligometastatic breast cancer and to suggest therapeutic approaches for optimal management of these patients.

RECENT FINDINGS

Unlike metastatic breast cancer, which remains incurable, patients with a limited number and extent of metastatic lesions, that is, oligometastatic disease, might achieve disease control and long-term survival when radical therapy of the primary tumor, if present, and metastatic disease is added to standard systemic therapy. However, the lack of a clear definition, variety of presentations, and the absence of biomarkers makes oligometastatic breast cancer a poorly understood clinical entity for which there is no standard treatment.

SUMMARY

Improvements in systemic therapies along with radical treatment of the primary tumor and metastatic lesions, together with optimization in the use of imaging tools, may help to increase the percentage of patients with metastatic breast cancer who achieve no-evidence-of-disease status or, at least, chronification of the disease. However, the fundamental question remains: which patients may benefit the most from a radical therapeutic approach? In this article, we propose strategies for the appropriate selection and comprehensive management of these patients.

Gene commander in the trash heap: Transcriptional regulation and ubiquitination modification mediated by RNF6 in carcinogenesis

RING finger protein 6 (RNF6), a RING finger protein, has been identified as a potential tumor promoter in several cancers. However, the exact mechanism of RNF6 in cancer remains elusive. As in various diseases, RNF6 may be involved in regulating cell growth, cell proliferation, invasion, cell cycle progression, apoptosis and cell adhesion through E3 ligase-mediated ubiquitination. Thus, the research on RNF6 is mainly focused on the ubiquitination of RNF6 in recent years. This article summarizes the role of RNF6 ubiquitination in various physiological and pathological mechanisms, such as Akt/mTOR signaling pathway, Wnt/β-catenin pathway, RNF6/ERα/Bcl-xL axis, and provides knowledge and understanding for the treatment of diseases.

The conversion of RAS status in metastatic colorectal cancer patients after first-line biological agent treatment

AIM

The aim was to investigate the RAS discordance between initial and recurrent metastasectomy specimens in metastatic colorectal cancer (mCRC) patients treated with chemotherapy (CT) plus biological agents in a first-line setting.

METHODS

Patients who had been treated with CT plus bevacizumab or cetuximab or panitumumab followed by R0 resection for potentially resectable colorectal cancer liver metastases were scanned. Among these, patients who developed resectable new metastases after a disease-free interval longer than 6 months were included in the study. We compared the RAS mutation status between the first biopsy and the second metastasectomy specimen.

RESULTS

A total of 82 mCRC patients treated with CT plus biological agents in a first-line setting were included in the study. The first biopsy assessment showed wild-type RAS tumours in 39 (47.6%) patients and mutant RAS tumours in 43 (52.4%) patients. The mean time for new operable liver metastasis after R0 resection was 15.5 months. In the second metastasectomy specimens, the numbers of wild-type and mutant RAS tumours were 30 (36.6%) and 52 (63.4%), respectively. The comparison with the first biopsy specimens showed RAS status conversions in 17 (20.7%) patients. Univariate comparison between patients with and without RAS status conversion revealed that grade, pathological T stage, wild-type RAS tumour and longer biological agent use time in the first-line treatment were significant factors for RAS conversion.

CONCLUSION

Our results suggest that re-biopsy is needed for an optimal second-line treatment decision in mCRC patients regardless of backbone biological agent, especially in patients with wild-type RAS mCRC.

Characteristics of Breast Cancer Metastasizing to Bone in a Mediterranean Population

Aim: This study examines clinicopathological, molecular, and radiological characteristics of breast cancer metastasizing to the bone in a Mediterranean population.

Methods: Cases of breast cancer with metastasis to bone were retrieved from the pathology department archives. Descriptive statistics and bivariate inferential statistics of retrieved clinical (demographic, focality, laterality, axillary lymph node status, and metastasis-free interval), radiological (skeletal site of bone metastasis, type of bone lesion), and microscopic (grade, subtype of breast cancer, lymphovascular status, perineural status, lymph node involvement, nodal extracapsular extension, molecular subtype) data were conducted.

Results: Out of 123 cases analyzed, 93.5% were ductal, 90% had axillary lymph node metastasis, 60.5% were luminal A, 59.6% were osteolytic, and 54.4% had grade III. Discordance in the status of ER, PR, and HER2 between the primary breast tumor and the corresponding bone metastases was noted, with the highest rate of change reported for PR (35.7%). Significance was detected at the level of difference between the subtype of breast cancer with regards to the radiologic features where the ductal subtype was found to be mostly osteolytic while the lobular subtype was mostly either osteoblastic or mixed (p-value=0.05). The metastasis-free interval was significantly associated with the number of metastatic bone lesions (P=0.001).

Conclusion: The significant association between metastasis-free interval and the number of metastatic bone lesions suggests that a higher interval allows more time for tumors to manifest multiple lesions. The high rate of discordance in the status of PR, ER, and HER2 was congruent with the literature highlighting the need to further investigate underlying mechanisms.

Profile and outcome of receptor conversion in breast cancer metastases: a nation-wide multicenter epidemiological study

Although receptor status including estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) of the primary breast tumors was related to the prognosis of breast cancer patients, little information is yet available on whether patient management and survival are impacted by receptor conversion in breast cancer metastases. Using data from the nation-wide multicenter clinical epidemiology study of advanced breast cancer in China (NCT03047889), we report the situation of retesting ER, PR and HER2 status for breast cancer metastases and evaluate the patient management and prognostic value of receptor conversion. In total, 3295 patients were analyzed and 1583 (48.0%) patients retesting receptor status for metastasis. Discordance in one or more receptors between the primary and the metastatic biopsy was found in 37.7% of women. Patients who remained hormone receptor (HR) positive in their metastases had similar progression-free survival of first-line and second-line treatment compared to patients with HR conversion (P > .05). In multivariate analysis, patients who showed ER conversion from negative to positive had longer disease-free survival (DFS) than patients who remained negative in their metastases (hazard ratio, 2.05; 95% confidence interval [CI], 1.45-2.90; P < .001). Patients with PR remained positive and had longer DFS than patients with PR conversion from negative to positive (hazard ratio, 0.56; 95% CI, 0.38-0.83; P = .004). Patients with PR conversion have shorter overall survival than patients with PR remained positive or negative (P = .016 and P = .041, respectively). Our findings showed that the receptors' conversions were common in metastatic breast cancer, and the conversion impacted the survival.

Sequestosome 1 (p62) accumulation in breast cancer cells suppresses progesterone receptor expression via argonaute 2

Sequestosome 1 (p62) is a multifunctional adapter protein involved in various physiological functions, such as selective autophagy and oxidative stress response. Hence, aberrant expression and defective regulation of p62 are thought to lead to the onset of various diseases, including cancer. The expression of p62 has been shown to be increased in breast cancer tissues, and is correlated with a poor prognosis. However, the role of p62 in the breast cancer pathophysiology is still unclear. Here, we aimed to analyze the effect of changes in p62 expression on breast cancer cell lines. DNA microarray analysis revealed that the expression of progesterone receptor (PR), which is one of the indices for the classification of breast cancer subtypes, was markedly suppressed by forced expression of p62. The protein expression of PR was also decreased by forced expression of p62, but increased by knockdown of p62. Moreover, we found that p62 knockdown induced the protein expression of argonaute 2 (AGO2). Luciferase reporter assay results showed that the gene expression of PR was promoted by AGO2. Furthermore, results revealed that overexpression of AGO2 partially rescued the decrease in PR expression induced by forced expression of p62. Collectively, our findings indicated that p62 accumulation suppressed the expression of AGO2, which in turn decreased the expression of PR, suggesting that p62 may serve as a marker of aggressive breast cancer and poor prognosis. Moreover, the p62-AGO2-PR axis was identified as a crucial signaling cascade in breast cancer progression.

Estrogen, progesterone, and human epidermal growth factor receptor 2 discordance between primary and metastatic breast cancer

Background

The estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) statuses are frequently discordant between the primary tumor and metastatic lesions in metastatic breast cancer. This can have important therapeutic implications.

Patients and methods

In all, 541 patients with available receptor statuses from both primary tumor and metastatic lesion treated at Heidelberg and Tuebingen University Hospitals between 1982 and 2018 were included.

Results

Statistically significant discordance rates of 14% and 32% were found for ER and PR. HER2 status was statistically insignificantly discordant in 15% of patients. Gain in HER2 positivity was associated with an improved overall survival, whereas loss of HR positivity was associated with worse overall survival. Antiendocrine treatment differed in 20% of cases before and after biopsy and HER2-directed treatment in 14% of cases.

Conclusions

Receptor statuses are discordant between primary tumor and metastasis in a considerable fraction of patients with metastatic breast cancer. Next to a highly presumed predictive value with respect to efficacy of endocrine and HER2-targeted therapy, discordance seems to provide prognostically relevant information. Where feasible, metastatic lesions should be biopsied in accordance with current guidelines.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05746-8) contains supplementary material, which is available to authorized users.

A preclinical PET dual-tracer imaging protocol for ER and HER2 phenotyping in breast cancer xenografts

BACKGROUND

Nuclear medicine is on the constant search of precision radiopharmaceutical approaches to improve patient management. Although discordant expression of the estrogen receptor (ER) and the human epidermal growth factor receptor 2 (HER2) in breast cancer is a known dilemma for appropriate patient management, traditional tumor sampling is often difficult or impractical. While 2-deoxy-2[18F]fluoro-D-glucose (18F-FDG)-positron emission tomography (PET) is an option to detect subclinical metastases, it does not provide phenotype information. Radiolabeled antibodies are able to specifically target expressed cell surface receptors. However, their long circulating half-lives (days) require labeling with long-lived isotopes, such as 89Zr, in order to allow sufficient time for tracer clearance from the blood compartment and to accumulate adequately in target tumors and, thus, generate high-quality PET images. The aim of this study was to develop a dual-tracer PET imaging approach consisting of a fast-clearing small molecule and a slow-clearing antibody. This approach was evaluated in a model consisting of mice harboring separate breast cancer xenografts with either an ER+/HER2- or ER-/HER2+ phenotype, comparable to human metastatic disease with intertumor heterogeneity. Lastly, the aim of our study was to determine the feasibility of specifically identifying these two important phenotypes in an acceptable time window.

METHODS

Female nude mice were subcutaneously implanted on opposite shoulders with the ER+/HER2- and ER-/HER2+ MCF-7 and JIMT-1 tumor cell lines, respectively. A second model was developed consisting of mice implanted orthotopically with either MCF-7 or JIMT-1 cells. Pharmacokinetic analysis, serial PET imaging, and biodistribution were first performed for [89Zr]Zr-DFO-trastuzumab (89Zr-T) up to 8 days post-injection (p.i.) in JIMT-1 bearing mice. Region-of-interest (ROI) and biodistribution-derived uptake (% injected-activity/gram of tissue [%IA/g]) values and tumor-to-background ratios were obtained. Results were compared in order to validate ROI and identify early time points that provided high contrast tumor images. For the dual-tracer approach, cohorts of tumor-bearing mice were then subjected to sequential tracer PET imaging. On day 1, mice were administered 4-fluoro-11β-methoxy-16α-[18F]-fluoroestradiol (4FMFES) which targets ER and imaged 45 min p.i. This was immediately followed by the injection of 89Zr-T. Mice were then imaged on day 3 or day 7. ROI analysis was performed, and uptake was calculated in tumors and selected healthy organs for all radiotracers. Quality of tumor targeting for all tracers was evaluated by tumor contrast visualization, tumor and normal tissue uptake, and tumor-to-background ratios.

RESULTS

89Zr-T provided sufficiently high tumor and low background uptake values that furnished high contrast tumor images by 48 h p.i. For the dual-tracer approach, 4FMFES provided tumor uptake values that were significantly increased in MCF-7 tumors. When 89Zr-T-PET was combined with 18F-4FMFES-PET, the entire dual-tracer sequential-imaging procedure provided specific high-quality contrast images of ER+/HER2- MCF-7 and ER-/HER2+ JIMT-1 tumors for 4FMFES and 89Zr-T, respectively, as short as 72 h from start to finish.

CONCLUSIONS

This protocol can provide high contrast images of tumors expressing ER or HER2 within 3 days from injection of 4FMFES to final scan of 89Zr-T and, hence, provides a basis for future dual-tracer combinations that include antibodies.

Discordance of immunohistochemical markers between primary and recurrent or metastatic breast cancer: A retrospective analysis of 107 cases

There is a discordance in the immunohistochemical markers between primary breast cancer and recurrent or metastatic breast cancer. This study aimed to assess the recent trends and prognostic features in the treatment of recurrent or metastatic breast cancerOverall, 107 patients were identified from January 2001 to August 2018 at the Peking Union Medical College Hospital, Beijing, and People's Republic of China to obtain a cohort of breast carcinoma patients who were confirmed to have recurrent or metastatic breast cancer by histopathology. We evaluated patient and tumor characteristics and examined the relationships between these factors and prognosis.The estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) positivity, and Ki67 index in primary breast cancer were 63.6% (68/107), 58.9% (63/107), 19.8% (21/106) and 75.8% (75/99), respectively, while those in recurrent or metastatic lesions were 60.6% (65/107) (P = .672), 46.7% (50/107) (P = 0.013), 23.8% (25/105) (P = 0.482)and 83.5%(81/97)(P = 0.178), respectively. The discordance rate of HER2 expression was 10.6% (11/104), while that of PR expression was 23.3% (21/90). HER2 was the most stable biomarker. The discordance rates for luminal A and HER2 were as high as 100% and 25%, respectively, while the luminal B and triple negative values were as low as 8.3% and 5.3%, respectively.ER and PR positivity and the Ki-67 index tended to increase due to recurrence or metastases; however, the discordance for PR and Ki-67 was high. PR is more variable than ER in the expression of primary and recurrent or metastatic breast cancer. The expression of HER2 receptor was the most stable and the discordance rate of triple negative breast cancer was the lowest. Therefore, although changes in biomarkers are due to recurrence or metastasis, pathological confirmation and exploration of markers are very important.

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.

Current applications of molecular testing on body cavity fluids

INTRODUCTION

Effusion cytology has a high sensitivity for the diagnosis of malignancy and provides abundant material for molecular testing. Effusion draining is a minimally invasive procedure with few complications.

MATERIALS AND METHODS

We performed a review of publications regarding the use of molecular testing in serous effusions.

RESULTS

In diagnostics, BAP-1 IHC and CDKN2A FISH are powerful tools for the diagnosis of malignant mesothelioma. FISH, PCR, and EBER-ISH work well in lymphomas. RT-PCR may enhance the diagnosis of secondary epithelial malignancies. In theranostics, molecular testing on serous effusions is widely reported for the detection of alterations in genes related to lung carcinomas, such as EGFR, ALK, ROS1, and BRAF. PD-L1 expression testing by immunohistochemistry (IHC) also seems to be viable in this type of sample. HER2 FISH and IHC provide actionable results in the context of breast malignancies. Results in serous effusions seem to be equivalent to tissue biopsies for most applications and across different molecular techniques. The most interesting technology is next-generation sequencing (NGS), given its ability to sequence multiple genes on a single sample and the decreasing costs that have closely followed increasing throughputs. Cell-free DNA from effusion supernatants might be the most promising area for future research, showing superiority to serum and even to cell-block samples in limited studies.

CONCLUSIONS

Molecular tests are viable in serous effusion specimens when sufficient material is available. Given the rising importance of molecular testing we expect this to be an active field of research in the near future.

Current and potential immunohistochemical biomarkers for prognosis and therapeutic stratification of breast carcinoma

The identification of biomarkers on cancer tissue samples could be obtained through several technologies. In this setting, the immunohistochemistry and in situ hybridization are accessible in most pathology laboratories. Particularly, immunohistochemistry can be used not only for diagnostic issues, but also to define prognostic classes and to define response to specific therapies. Particularly the last applications have been firstly developed in the breast cancer pathology. In addition, the development of molecular classification proposed some prognostic/predictive classes that could be easily defined by immunohistochemistry. Thus, the role of the pathologists has become increasingly important in the definition of prognosis and in the choice therapy, because the immunohistochemical biomarkers are used to guide treatment, to classify breast cancer into biologically and prognostically distinct subtypes. In this review, we will provide information on the current application of the immunohistochemical biomarkers useful in the management of breast cancer patients. Moreover, we consider the application of immunohistochemistry in the definition of the most promising biomarkers derived from molecular studies of the breast cancer, that in the future could integrate the characterization of breast cancer into clinical practice.

The Prognostic Impact of Hormonal Receptor and HER-2 Expression Discordance in Metastatic Breast Cancer Patients

Background

Hormone receptor (HR) and human epidermal growth factor receptor (HER2) discordance between primary and metastatic breast cancer lesions is common. However, its impact on long-term survival remains unclear. We aimed to determine the prognostic value of this discordance in patients with metastaticf breast cancer (MBC).

Methods

A total of 270 patients with MBC who were underwent re-biopsy of progressive metastases at Zhejiang Cancer Hospital from January 1, 2012 to December 31, 2015 with patients consent and then review their primary tumors pathological findings. The HR and HER2 status in both primary and progressive metastatic lesions was determined by immunohistochemistry and/or fluorescence in situ hybridization. The discordance rates were correlated with the clinicopathologic characteristics, metastatic lesions, salvage treatment, and survival analysis in this population.

Results

A total of 142 (52.6%) MBC patients were diagnosed with discordant HR and HER2 status. Alterations in estrogen receptor (ER), progesterone receptor (PR), and HER2 status were observed in 20.70%, 37.78%, and 11.48% cases, respectively. Chemotherapy (P=0.0192) and endocrine therapy (P=0.048) significantly affected the conversion of HR status. Endocrine therapy was positively correlated with PR discordance (P=0.002), while ER discordance was associated with adjuvant chemotherapy (P=0.031). Survival analysis showed that ER status alterations between primary and metastatic lesions were associated with overall survival (P=0.002). The clinical prognosis was significantly worse with HR losses than with persistent HR positivity (P=0.023). In Cox multivariate analysis, the loss of HR expression and conversion to triple negative were independent prognostic indicators.

Conclusion

Discordance in HR status between primary and metastatic lesions may impact the prognosis of MBC, and HR conversion has independent prognostic value.

Combined use of SOX10 and GATA3 in mammary carcinoma

The complementary coverage of different subsets of breast cancer by GATA3 and SOX10 makes their use in combination appealing for routine clinical use, but study of these markers has been largely limited to cases with high or absent ER expression. Here we report SOX10 and GATA3 immunostaining in parallel using a tissue microarray containing 246 invasive breast carcinoma cases with a range of ER expression. GATA3 and SOX10 were positive in 93 % (229/246) and 15 % (38/246) of cases overall and in 63 % (24/38) and 74 % (28/38) of triple negative breast carcinomas (TNBC), respectively; SOX10 was positive in 15 of the 17 cases that lacked GATA3 expression (88 %). SOX10 was also positive in 3 % (6/196) of ER + cases, including 50 % of cases with low ER (3/6), 20 % with intermediate ER (3/15), and 0 % with high ER (n = 175), so that ER-low cases more strongly resembled TNBC than those with high ER expression. GATA3 expression was lower in cases that co-expressed SOX10 in comparison to those that were positive for GATA3 alone. Less than 1 % (2/246) of cases were negative for both GATA3 and SOX10. Therefore, SOX10 is a useful adjunct to GATA3 in the detection of TNBC and cases with low ER expression and/or reduced GATA3 intensity relative to that typical of breast cancers with higher ER expression. Moreover, given such high sensitivity, metastatic tumors lacking either GATA3 or SOX10 are unlikely to be of breast origin. Additional study is necessary to determine the extent to which SOX10 may also improve specificity and to characterize its biologic significance in breast cancers with low ER expression.

Precision health for breast cancer metastasis: biomaterial scaffolds as an engineered metastatic niche to define, study, and monitor metastatic progression

Metastasis represents the greatest challenge to treatment of cancer patients. Biomaterial scaffolds that recruit tumor cells to a defined site in vivo are an emerging platform for the diagnosis, treatment, and study of metastasis. Recruitment of immune cells and metastatic tumor cells to a defined location provides a precision health platform to assess current clinical cancer biomarkers in a metastatic setting, and to define the next generation of biomarkers. These platforms represent an opportunity to create a molecular staging of metastasis that could aid in both the early diagnosis and treatment of metastasis.

Proceedings of the American Society of Cytopathology companion session at the 2019 United States and Canadian Academy of Pathology Annual meeting, part 2: effusion cytology with focus on theranostics and diagnosis of malignant mesothelioma

We live in the "era" of minimally invasive procedures, molecular testing, and personalized care. Effusions have a high sensitivity and will often yield diagnostic cytological material. The companion session presented by the American Society of Cytopathology at the 2019 United States and Canadian Academy of Pathology meeting outlined our current and future projected practices in characterizing, managing, and diagnosing serous cavity fluids. In this second part, the role of theranostics and the diagnosis of malignant mesothelioma, as was discussed at the meeting, have been highlighted. In theranostics, a vast amount of data has been reported regarding the epidermal growth factor receptor and related molecules. Some studies have also reported on HER2 immunohistochemistry and fluorescence in situ hybridization. This follows the most active areas of research in targeted therapy. Furthermore, during this session, malignant mesothelioma was extensively discussed. The cytologic diagnosis of malignant mesothelioma in effusion specimens has been controversial; however, a definitive diagnosis will be possible in many cases. Radiologic information should be sought, because the radiologist can often provide a definite or very likely diagnosis of malignancy. Microscopically, high cellularity and/or numerous balls of cells or papillary groups will favor the diagnosis of mesothelioma. It is important to exclude metastatic carcinoma with a broad-spectrum carcinoma marker, of which claudin-4 has been the best, because it will not cross react with mesothelioma. BAP1 and MTAP immunohistochemistry and CDKN2A fluorescence in situ hybridization are very useful adjunctive techniques for separating benign from malignant mesothelial proliferations. The use of 2 of these approaches together will produce a sensitivity of 80% to 90% for epithelial mesotheliomas in the pleura, although the sensitivity has been lower in the peritoneal cavity.

Clinical significance of evaluating hormone receptor and HER2 protein using cell block against metastatic breast cancer: a multi-institutional study

Hormone receptor and human epidermal growth factor receptor 2 (HER2) protein tests in metastatic breast cancer tissue are recommended in the guidelines of the American Society of Clinical Oncology/American Pathology Association. As part of a multi-institutional study by the National Hospital Organization, we conducted an investigation to examine these molecular markers, using cytological specimens as a substitute for tissue specimens from breast cancer metastasis. To confirm the usefulness of receptors tested in metastatic lesions, the treatment course of registered metastatic breast cancer patients was analyzed. During the April 2015 to March 2016 registration period, there were 62 registrations. Types of metastatic lesions include pleural fluid (44 samples), ascites (14 samples), lymph nodes (2 samples), pericardial fluid (1 sample), and dorsal subcutaneous mass (1 sample). A stable test result was obtained by adopting the receptor examination method, using cell block for immunostaining cytological specimens. The discordance rates of estrogen receptor (ER), progesterone receptor (PR), and HER2 protein expression were 18.2% (95% confidence interval (CI): 7.9–28.8%), 36.4% (95% CI: 23.7–49.1%), and 8.2% (95% CI: 0.1–16.3%), respectively, between the primary tumor and metastatic lesion. Patients who changed from primary negative to metastatic positive ER status had taken a significantly longer time for metastatic foci to appear. Patients with positive ER status in metastatic lesions had significantly better prognosis than ER-negative cases (P = 0.030) by the Log-Rank test. The ER status of the metastatic lesion and the metastatic site were independent prognostic factors by Cox multivariate analysis. Receptor examination with cytological specimens in metastatic lesions has been useful as it provides guidance for the treatment of metastatic breast cancer.

Investigating circulating tumor cells and distant metastases in patient-derived orthotopic xenograft models of triple-negative breast cancer

BACKGROUND

Circulating tumor cells (CTCs) represent a temporal "snapshot" of a patient's cancer and changes that occur during disease evolution. There is an extensive literature studying CTCs in breast cancer patients, and particularly in those with metastatic disease. In parallel, there is an increasing use of patient-derived models in preclinical investigations of human cancers. Yet studies are still limited demonstrating CTC shedding and metastasis formation in patient-derived models of breast cancer.

METHODS

We used seven patient-derived orthotopic xenograft (PDOX) models generated from triple-negative breast cancer (TNBC) patients to study CTCs and distant metastases. Tumor fragments from PDOX tissue from each of the seven models were implanted into 57 NOD scid gamma (NSG) mice, and tumor growth and volume were monitored. Human CTC capture from mouse blood was first optimized on the marker-agnostic Vortex CTC isolation platform, and whole blood was processed from 37 PDOX tumor-bearing mice.

RESULTS

Staining and imaging revealed the presence of CTCs in 32/37 (86%). The total number of CTCs varied between different PDOX tumor models and between individual mice bearing the same PDOX tumors. CTCs were heterogeneous and showed cytokeratin (CK) positive, vimentin (VIM) positive, and mixed CK/VIM phenotypes. Metastases were detected in the lung (20/57, 35%), liver (7/57, 12%), and brain (1/57, less than 2%). The seven different PDOX tumor models displayed varying degrees of metastatic potential, including one TNBC PDOX tumor model that failed to generate any detectable metastases (0/8 mice) despite having CTCs present in the blood of 5/5 tested, suggesting that CTCs from this particular PDOX tumor model may typify metastatic inefficiency.

CONCLUSION

PDOX tumor models that shed CTCs and develop distant metastases represent an important tool for investigating TNBC.

Cancer Testis Antigen Promotes Triple Negative Breast Cancer Metastasis and is Traceable in the Circulating Extracellular Vesicles

Triple negative breast cancer (TNBC) has poor survival, exhibits rapid metastases, lacks targeted therapies and reliable prognostic markers. Here, we examined metastasis promoting role of cancer testis antigen SPANXB1 in TNBC and its utility as a therapeutic target and prognostic biomarker. Expression pattern of SPANXB1 was determined using matched primary cancer, lymph node metastatic tissues and circulating small extracellular vesicles (sEVs). cDNA microarray analysis of TNBC cells stably integrated with a metastasis suppressor SH3GL2 identified SPANXB1 as a potential target gene. TNBC cells overexpressing SH3GL2 exhibited decreased levels of both SPANXB1 mRNA and protein. Silencing of SPANXB1 reduced migration, invasion and reactive oxygen species production of TNBC cells. SPANXB1 depletion augmented SH3GL2 expression and decreased RAC-1, FAK, A-Actinin and Vinculin expression. Phenotypic and molecular changes were reversed upon SPANXB1 re-expression. SPANXB1 overexpressing breast cancer cells with an enhanced SPANXB1:SH3GL2 ratio achieved pulmonary metastasis within 5 weeks, whereas controls cells failed to do so. Altered expression of SPANXB1 was detected in the sEVs of SPANXB1 transduced cells. Exclusive expression of SPANXB1 was traceable in circulating sEVs, which was associated with TNBC progression. SPANXB1 represents a novel and ideal therapeutic target for blocking TNBC metastases due to its unique expression pattern and may function as an EV based prognostic marker to improve TNBC survival. Uniquely restricted expression of SPANXB1 in TNBCs, makes it an ideal candidate for targeted therapeutics and prognostication.