Circulating epithelial cells in patients with benign colon diseases

BACKGROUND

Detection of circulating tumor cells (CTCs) in the peripheral blood is a rapidly developing research field with clear clinical implications for the staging and monitoring of cancer patients. Current CTC assays, including the US Food and Drug Administration-cleared CellSearch® system, typically use markers [e.g., cytokeratins (CKs), the transmembrane protein EpCAM (epithelial cell adhesion molecule)] that are expressed on normal and malignant epithelial cells but not on the surrounding normal leukocytes.

METHODS

We enrolled 53 patients with benign colon diseases (e.g., diverticulosis, benign polyps, Crohn disease, ulcerative rectocolitis, colonic endometriosis) and analyzed their peripheral blood with 2 previously validated CTC assays: the epithelial immunospot (EPISPOT) assay and the CellSearch system. The EPISPOT assay detects only viable, CK19-releasing CTCs that were enriched by depletion of CD45(+) leukocytes, whereas the CellSearch system detects CK-positive CTCs after positive EpCAM-based immunomagnetic enrichment.

RESULTS

In patients with benign colon diseases, positive events that met the criteria for "tumor cells" were detected with both the CellSearch system (11.3%) and the CK19-EPISPOT assay (18.9%), whereas no positive events were detected in samples from healthy volunteers. Positive events were detected most frequently in patients with diverticulosis and Crohn disease. All positive events lacked expression of CD45, a common leukocyte antigen.

CONCLUSIONS

These results indicate that patients with benign inflammatory colon diseases in particular can harbor viable circulating epithelial cells that are detectable with current CTC assays. This finding points to the need for further molecular characterization of circulating epithelial cells and has important implications for the use of CTC testing.

P4-07-13: Prognostic Impact of Circulating Tumor Cells Assessed with the Cell Search Assay and Adna Test Breast in Metastatic Breast Cancer Patients – The DETECT Study

Background

Over the last decade circulating tumor cells (CTC) were established as a prognostic factor in breast cancer patients. However, there are very limited studies comparing different test methods, although several are available.The DETECT trial for metastatic breast cancer patients was designed to investiate the prognostic impact of CTC. Here, we report on the prognostic relevance of CTC testing with different detection methods.

Material and Methods: Patients with primary metastatic breast cancer or metastatic recurrence were prospectively enrolled in this multicenter trial. CTC were detected using the FDA-approved Cell Search® assay applying immunocytochemistry and the RNA-based Adna Test Breast Cancer™. After a median follow-up of 11 months the first survival data are now presented.

Results: Both methods could be performed in 221 patients. Using the CellSearch™ assay 116 of 221 patients were CTC-positive based on the cut-off level of 5 cells. Presence of CTC was associated with the site of metastatic disease. The OS was 15.4 months in CTC positive pts. (95%-CI: 13.5−17.1 mths) compared to 20.4 mths. in CTC negative pts. (19.1−21.9 mths.; p<0.001). In the multivariate analysis presence of CTC was the only independent predictor for overall survival (HR: 3.4, 95%-CI: 1.7−6.3) including tumorbiological factors, menopausal status, number and sites of metastatic disease. The progression-free survival was not correlated with CTC status in our cohort receiving different types of systemic treatment (p=0.197). When the AdnaTest Breast was performed, 88 of 221 (40%) patients were CTC positive. Except for HER2 status, no correlation could be observed between CTC positivity and any of the clinicopathological factors. CTC positivity assessed by the AdnaTest Breast has no impact on PFS and OS. A multivariate analysis was therefore not performed.

Conclusions: Currently, several different tests are available for CTC detection. Only a few tests have been approved by the FDA and been validated in large clinical trials. Therfore, it will be important to compare new techniques with the Cell Search assay.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-13.

P4-07-14: Circulating Tumor Cells (CTCs) Detection and HER2 Profiling by CellSearch® in Non-Metastatic Breast Cancer: An International Ring Study To Assess Inter-Reader Variability

Background: Preliminary results from the Success and Remagus trials showed that CTC detection by CellSearch® has adverse prognostic value in non-metastatic breast cancer. Moreover, several investigators have characterized HER2 expression on CTCs in early breast cancer. Since the majority of CTC-positive women with non-metastatic breast cancer have only 1 CTC detected / blood volume analyzed, we wanted to evaluate the inter-reader variability in this setting. This is a crucial step before moving forward with multi-lab/multi-center prospective testing of the clinical utility of the CellSearch® technology in non-metastatic breast cancer.

Methods: Five galleries of CellSearch® images from 3 European and one US institution (a total of 307 images) were mailed to 22 independent readers from 14 European and US academic laboratories and 8 readers from two CellSearch® Veridex laboratories in a blinded fashion. These images came mainly from studies on CTC and/or HER2−positive CTC detection in breast cancer and included healthy women (negative controls), women with metastatic (positive controls) and non-metastatic disease (Pierga et al SABCS 2010, Pierga et al ASCO 2011, Riedthorf et al CCR 2010, Ignatiadis et al PLoS ONE 2011). Each reader reported the images as either CTC-negative or CTC-positive/HER2−negative or CTC-positive/HER2−positive. Kappa statistics were used to assess inter-reader agreement. The 8 Veridex readers were summarized by a majority voting system to derive a gold standard in order to compare each independent reader using discordance rates.

Results: Kappa statistics showed moderate to good agreement between independent readers depending on the gallery evaluated (gallery 1 K: 0.55, gallery 2 K:0.57 gallery 3 K:0.64, gallery 4 K:0.72, gallery 5 K:0.85). These differences were attributed to differences in scoring difficulty of each gallery. Discordances in CTC-positive vs CTC-negative events between each reader and the gold standard ranged from 2.3%-31.3% with 7 readers showing discordance rates <5%, 11 readers between 5–10%, 10 readers between 10–14% and only 2 readers showing discordance rates >14% as compared to the gold standard (median discordance rate: 9.3%). Image analysis showed that investigators with high discordance rates compared to the Veridex gold standard were not always taking into account “morphological characteristics” for defining an event as CTC-positive. Discordant results between readers were mainly due to discordance in CTC definition and to a lesser extent in the definition of HER2−positivity. Indeed, discordances in assigning a CTC-positive event as either HER2−negative or HER2−positive ranged from 0.3−13.7% with 19 readers showing discordance rates <5%, 7 readers between 5–10% and 4 readers with discordance rates >10% (median discordance rate: 3.9%).

Conclusion: In non-metastatic breast cancer, we observed low discordance between most independent readers and the gold standard for defining a CellSearch® event as CTC with very few readers showing high discordance rates. Concordance can be improved through appropriate training and the use of all the tools provided by the CellSearch® system for image interpretation.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-14.

VCAM-1 promotes osteolytic expansion of indolent bone micrometastasis of breast cancer by engaging α4β1-positive osteoclast progenitors

Breast cancer patients often develop locoregional or distant recurrence years after mastectomy. Understanding the mechanism of metastatic recurrence after dormancy is crucial for improving the cure rate for breast cancer. Here, we characterize a bone metastasis dormancy model to show that aberrant expression of vascular cell adhesion molecule 1 (VCAM-1), in part dependent on the activity of the NF-κB pathway, promotes the transition from indolent micrometastasis to overt metastasis. By interacting with the cognate receptor integrin α4β1, VCAM-1 recruits monocytic osteoclast progenitors and elevates local osteoclast activity. Antibodies against VCAM-1 and integrin α4 effectively inhibit bone metastasis progression and preserve bone structure. These findings establish VCAM-1 as a promising target for the prevention and inhibition of metastatic recurrence in bone.

VCAM-1 promotes osteolytic expansion of indolent bone micrometastasis of breast cancer by engaging α4β1-positive osteoclast progenitors

Breast cancer patients often develop locoregional or distant recurrence years after mastectomy. Understanding the mechanism of metastatic recurrence after dormancy is crucial for improving the cure rate for breast cancer. Here, we characterize a bone metastasis dormancy model to show that aberrant expression of vascular cell adhesion molecule 1 (VCAM-1), in part dependent on the activity of the NF-κB pathway, promotes the transition from indolent micrometastasis to overt metastasis. By interacting with the cognate receptor integrin α4β1, VCAM-1 recruits monocytic osteoclast progenitors and elevates local osteoclast activity. Antibodies against VCAM-1 and integrin α4 effectively inhibit bone metastasis progression and preserve bone structure. These findings establish VCAM-1 as a promising target for the prevention and inhibition of metastatic recurrence in bone.

Quantitative high-resolution genomic analysis of single cancer cells

During cancer progression, specific genomic aberrations arise that can determine the scope of the disease and can be used as predictive or prognostic markers. The detection of specific gene amplifications or deletions in single blood-borne or disseminated tumour cells that may give rise to the development of metastases is of great clinical interest but technically challenging. In this study, we present a method for quantitative high-resolution genomic analysis of single cells. Cells were isolated under permanent microscopic control followed by high-fidelity whole genome amplification and subsequent analyses by fine tiling array-CGH and qPCR. The assay was applied to single breast cancer cells to analyze the chromosomal region centred by the therapeutical relevant EGFR gene. This method allows precise quantitative analysis of copy number variations in single cell diagnostics.

High-resolution analyses of copy number changes in disseminated tumor cells of patients with breast cancer

The presence of disseminated tumor cells (DTCs) in bone marrow (BM) identifies breast cancer patients with less favorable outcome. Furthermore, molecular characterization is required to investigate the malignant potential of these cells. This study presents a single-cell array comparative genomic hybridization (SCaCGH) method providing molecular analysis of immunomorphologically detected DTCs. The resolution limit of the method was estimated using the cancer cell line SK-BR-3 on 44 and 244k arrays. The technique was further tested on 28 circulating tumor cells and four hematopoietic cells (HCs) from peripheral blood (n = 8 patients). The SCaCGH method was finally applied to 24 DTCs, three immunopositive cells morphologically classified as probable HCs from breast cancer patients and five HC controls from BM (n = 7 patients plus n = 1 healthy donor). The frequency of copy number changes of the DTCs revealed similarities with primary breast tumor samples. Three of the patients had available profiles for DTCs and the corresponding tumor tissue from primary surgery. More than two-third of the analyzed DTCs disclosed equivalent changes, both to each other and to the corresponding primary disease, whereas the rest of the cells showed balanced profiles. The probable HCs revealed either balanced profiles (n = 2) or changes comparable to the tumor tissue and DTCs (n = 1), indicating morphological overlap between HCs and DTCs. Similar aberration patterns were visible in DTCs collected at diagnosis and at 3 years relapse-free follow-up. SCaCGH may be a powerful tool for the molecular characterization of DTCs.

Disseminated tumor cells in pancreatic cancer-an independent prognosticator of disease progression and survival

Pancreatic cancer is one of the most devastating cancers with a 6-month median survival and a 5-year survival rate of 3-5%. Still important aspects of its aggressive biology remain elusive and advanced therapeutic regimens have not been substantially successful. We investigated the prognostic role of disseminated tumor cells (DTC) in bone marrow, a reservoir for early DTC potentially contributing to metastatic progression, of pancreatic cancer patients. After exclusion of patients with different postsurgery diagnosis or missing DTC status (n = 40) a total of 175 patients remained for final analyses. One-hundred and nineteen patients were male and 96 female with a median age of 67 years, 96 patients underwent complete resection. Bone marrow aspirates taken at primary surgery were analyzed for DTC by an immunocytochemical cytokeratin assay and correlated to survival data. Overall 13.7% of patient samples (24/175) harbored DTC in their bone marrow. Histopathological parameters did not correlate significantly. Univariate survival analysis revealed a borderline significant correlation between DTC and decreased progression-free survival (p = 0.069), and was significant for overall survival (p = 0.036). Regarding patients with resected tumors, the respective p-values were 0.058 for progression-free and 0.016 for overall survival. Importantly, the prognostic influence was independent from other risk factors as shown by multivariate analyses for progression-free (p = 0.030, HR: 2.057; CI (95%): 1.073-3.943) and overall survival (p = 0.006, HR: 2.283; CI (95%): 1.260-4.135). The presence of DTC in bone marrow is a strong and independent prognostic factor of survival in patients with pancreatic cancer. Thus, bone-targeting may be a new future therapeutic option for DTC-positive patients.

The anti-interleukin-6 antibody siltuximab down-regulates genes implicated in tumorigenesis in prostate cancer patients from a phase I study

BACKGROUND

Interleukin-6 (IL-6) is associated with prostate cancer morbidity. In several experimental models, IL-6 has been reported to have anti-apoptotic and pro-angiogenic effects. Siltuximab (CNTO 328) is a monoclonal anti-IL-6 antibody which has been successfully applied in several models representing prostate cancer. This study was designed to assess preliminary safety of siltuximab in patients with early prostate cancer.

PATIENTS AND METHODS

Twenty patients scheduled to undergo radical prostatectomy received either no drug or siltuximab (6 mg/kg, five patients per group with administration once, two times, and three times prior to surgery). Blood samples were collected for pharmacokinetic and pharmacodynamic analyses. Expression of elements of IL-6 signaling pathways was analyzed in tumor tissue by immunohistochemistry. Gene analysis in tumor specimens was performed with the DASL array.

RESULTS

No adverse events related to siltuximab were observed. Patients treated with siltuximab presented with higher levels of proliferation and apoptosis markers. Following a single dose, serum concentrations of siltuximab declined in a biexponential manner. This study revealed a decrease in phosphorylation of Stat3 and p44/p42 mitogen-activated protein kinases. In addition, gene expression analyses indicate down-regulation of genes immediately downstream of the IL-6 signaling pathway and key enzymes of the androgen signaling pathway.

CONCLUSIONS

Preliminary safety of siltuximab is favorable. Future studies in which siltuximab could be combined with androgen-deprivation therapy and experimental therapies in advanced prostate cancer are justified.

Prospective evaluation of serum tissue inhibitor of metalloproteinase 1 and carbonic anhydrase IX in correlation to circulating tumor cells in patients with metastatic breast cancer

INTRODUCTION

Circulating tumor cells (CTCs) reflect aggressive tumor behavior by hematogenous tumor cell dissemination. The tissue inhibitor of metalloproteinase 1 (TIMP-1) plays a role in tissue invasion and is also involved in angiogenesis, abrogation of apoptosis and in chemoresistance. Carbonic anhydrase IX (CAIX) is a metalloenzyme involved in cell adhesion, growth and survival of tumor cells. The aim of the study was to investigate whether serum concentrations of TIMP-1 and CAIX are associated with the detection of CTC in metastatic breast cancer.

METHODS

Blood was obtained in a prospective multicenter setting from 253 patients with metastatic breast cancer at the time of disease progression. Serum TIMP-1 and CAIX were determined using commercial ELISA-kits (Oncogene Science). CTC were detected with the CellSearch system (Veridex).

RESULTS

Five or more CTCs were detected in 122 patients out of 245 evaluable patients (49.8%). Out of 253 metastatic patients 70 (28%) had serum TIMP-1 levels above 454 ng/mL. Serum CAIX was elevated above 506 ng/mL in 90 (35%) patients. Both serum markers had prognostic significance. Median progression free survival (PFS) was 7.2 months with elevated TIMP-1 vs. 11.4 months with non-elevated levels (p < 0.01). OS was 11.5 vs. 19.1 months (p < 0.01). Median PFS was 7.5 months with elevated CAIX vs. 11.7 months with non-elevated levels (p < 0.01), overall survival (OS) was 13.4 months vs. 19.1 months (p < 0.01). In patients with five or more CTCs, serum levels were above the cut-off for CAIX in 47% vs. 25% in those with less than five CTCs (p = 0.01). For TIMP-1, 37% patients with five or more CTCs had elevated serum levels and 17% of patients with less than five CTCs (p = 0.01). Including TIMP-1, CAIX, CTC and established prognostic factors in the multivariate analysis, the presence of CTCs, the therapy line and elevated CAIX remained independent predictors of OS.

CONCLUSIONS

Elevated serum levels of the invasion markers TIMP-1 and CAIX in metastatic breast cancer are prognostic markers and are associated with the presence of CTCs. Whether increased secretion of TIMP-1 and/or CAIX might directly contribute to tumor cell dissemination remains to be elucidated in further investigations.

TRIAL REGISTRATION

Current Controlled Trials: ISRCTN59722891.

The interrelating dynamics of hypoxic tumor microenvironments and cancer cell phenotypes in cancer metastasis

The interrelating dynamics of the primary tumor cells and their surrounding microenvironment might determine phenotypic characteristics of disseminated tumor cells and contribute to cancer metastasis. Cytoprotective mechanisms (e.g., energy metabolism control, DNA damage response, global translation control and unfolded protein response) exert selective pressure in the tumor microenvironment. In particular, adaptation to hypoxia is vital for survival of malignant cells in the tumor and at distant sites such as the bone marrow. In addition to the stress response, the ability of tumor cells to undergo certain cellular re-differentiation programmes like the epithelial-mesenchymal transition (EMT), which is linked to cancer stemness, appears to be important for successful cancer cell spread. Here we will discuss the selection pressures that eventually lead to the formation of overt metastases. We will focus the properties of the microenvironment including (i) metabolic and cytoprotective programs that ensure survival of disseminated tumor cells, (ii) blood vessel structure, and (iii) the hypoxia-normoxia switch as well as intrinsic factors affecting the evolvement of novel tumor cell populations.

Disseminated tumor cells in the bone marrow of patients with ductal carcinoma in situ

Detection of disseminated tumor cells (DTCs) in bone marrow is an independent prognostic factor in primary breast cancer. Here, we conducted a proof-of-principle study to evaluate whether this tumor cell spread occurs already in patients with ductal carcinoma in situ (DCIS). After preoperative screening by stereotactic core biopsy, 30 consecutive women with DCIS were included. Bone marrow aspirates, taken at the time of primary surgery, were subjected to DTC detection by a standardized immunoassay using the established monoclonal anti-cytokeratin antibodies A45-B/B3 and AE1/AE3. DTCs were detected in 4 of 19 cases of pure DCIS (21.1%) and in four of seven cases of DCIS with microinvasion (57.1%). After a median follow-up time of 22 months, two initially DTC-positive patients suffered from contralateral carcinoma and contralateral DCIS at months 12 and 30, respectively, whereas the remaining patients were relapse free. Thus, hematogenous tumor cell dissemination into bone marrow is an early event in breast cancer development.

Overexpression of TACE and TIMP3 mRNA in head and neck cancer: association with tumour development and progression

BACKGROUND

TACE/ADAM17 is a transmembranous protease that cleaves membrane-bound growth factors like EGFR ligands. TACE-dependent proteolysis is regulated by its inhibitor, tissue inhibitor of metalloproteinases 3 (TIMP3). This study analyses the role of TACE and TIMP3 mRNA expression in squamous cell carcinomas of the head and neck (HNSCCs).

METHODS

We analysed TACE and TIMP3 mRNA expression in HNSCCs from 106 patients by RNA in situ hybridisation.

RESULTS

TACE mRNA was upregulated in HNSCCs compared with dysplastic (P<0.05) and normal epithelia (P<0.001), with strong hybridisation signals in 21.9% of invasive tumour tissues and 4.5% of dysplasia. Elevated mRNA levels were accompanied by increased amounts of TACE protein in HNSCCs. TIMP3 mRNA expression in HNSCC-associated stroma was significantly higher than in the stroma adjacent to dysplastic or normal epithelia. Expression of TACE mRNA in HNSCCs was associated with tumour stage (P=0.019) and regional lymph node metastasis (P=0.009). Furthermore, levels of TACE mRNA in HNSCCs correlated with the expression of TIMP3 mRNA in HNSCC-associated stroma. Concomitantly, patients expressing high levels of TACE and TIMP3 mRNA showed significantly reduced overall survival compared with those with low mRNA levels.

CONCLUSION

Our results indicate an important role of TACE and TIMP3 during development and progression of HNSCCs.

Advancing personalized cancer therapy by detection and characterization of circulating carcinoma cells

Early dissemination, blood circulation, or homing of single tumor cells in bone marrow and other organs is usually undetectable at primary diagnosis, even by high resolution imaging technologies. However, ultrasensitive approaches now enable the detection of "occult" tumor cells. Many researchers are currently focusing on circulating tumor cells (CTC) in peripheral blood, and several publications have described associations of CTC in patients with metastatic cancer and worse prognosis. However, evidence has emerged that the currently used detection methods lack sensitivity or specificity to track all CTC, especially those that have lost characteristic epithelial features. Therefore, new developments in this field are of utmost interest and will be reviewed here. Moreover, molecular CTC analysis will provide insights into the selection of tumor cells and resistance mechanisms in patients undergoing systemic therapies. This information might support assessing individual prognosis, stratifying patients at risk to systemic therapies, and monitoring therapeutic efficacy.

External quality assurance of circulating tumor cell enumeration using the CellSearch(®) system: a feasibility study

BACKGROUND

Circulating tumor cells (CTCs) are cells that have detached from solid tumors and entered the blood. CTCs can be detected, among others, by semi-automated immunomagnetic enrichment and image cytometry using CellSearch® (Veridex, Raritan, NJ). We studied the feasibility of external quality assurance (EQA) of the entire CellSearch procedure from blood draw to interpretation of results in multiple laboratories.

METHODS

Blood samples from six cancer patients and controls were distributed to 14 independent laboratories to test between-laboratory, between-assay, and between-instrument variation. Additionally, between-operator variability was assessed through the interpretation of blinded images of all blood samples on a website.

RESULTS

Shipment and storage of samples had no influence on CTC values. Between-instrument (coefficient of variation (CV) < 12%) and between-assay variation was low (CV ≤ 20%), indicating high reproducibility. However, between-laboratory CV ranged from 45 to 64%. Although inter-operator agreement on image interpretation (Fleiss' κ statistics) ranged from "substantial" to "almost perfect," image interpretation, particularly of samples containing high numbers of apoptotic cells, was the main contributor to between-laboratory variation.

CONCLUSIONS

This multicenter study shows the feasibility of an EQA program for CTC detection in patient samples, and the importance of continuation of such a program for the harmonization of CTC enumeration.

Detection of circulating tumour cells in peripheral blood of patients with advanced non-metastatic bladder cancer

OBJECTIVE

• To prospectively detect and evaluate the biological significance of circulating tumour cells (CTC) in patients with bladder cancer, especially in those patients with non-metastatic, advanced bladder cancer (NMABC).

PATIENTS AND METHODS

• Between July 2007 and January 2009, blood samples of 50 consecutive patients with localized bladder cancer and five patients with metastatic disease scheduled for cystectomy were prospectively investigated for CTC. Peripheral blood (7.5 ml) was drawn before cystectomy. • Detection of CTC was performed using the USA Food and Drug Administration-approved CellSearch(TM) system. Data were compared with the clinical and histopathological findings.

RESULTS

• CTC were detected in 15 of 50 patients (30%) with non-metastatic disease and five of five patients with metastatic disease. The overall mean number of CTC was 33.7 (range: 1-372; median: 2). In non-metastatic patients, the mean number of CTC was 3.1 (range: 1-11; median: 1). Except for a univariate association between CTC with vessel infiltration (P= 0.047), all other common clinical and histopathological parameters did not reveal a significant correlation with CTC detection. • A median 1-year follow up was available for 53 patients (96.4%). Ten out of 19 preoperatively CTC-positive patients died as a result of cancer progression. • CTC-positive patients showed significantly worse overall (P = 0.001), progression-free (P < 0.001) and cancer specific survival (P < 0.001) compared to preoperatively CTC-negative patients.

CONCLUSION

• This is the largest study demonstrating that detection of CTC in NMABC patients is feasible using the CellSearch(TM) system. Our findings suggest that the presence of CTC may be predictive for early systemic disease.

Detection and HER2 expression of circulating tumor cells: prospective monitoring in breast cancer patients treated in the neoadjuvant GeparQuattro trial

PURPOSE

This study was aimed at detecting and characterizing circulating tumor cells (CTC) before and after neoadjuvant therapy (NT) in the peripheral blood of patients with breast cancer.

EXPERIMENTAL DESIGN

The clinical trial GeparQuattro incorporated NT approaches (epirubicin/cyclophosphamide prior to randomization to docetaxel alone, docetaxel in combination with capecitabine, or docetaxel followed by capecitabine) and additional trastuzumab treatment for patients with HER2-positive tumors. We used the Food and Drug Administration-approved CellSearch system for CTC detection and evaluation of HER2 expression and developed HER2 immunoscoring for CTC.

RESULTS

We detected > or =1 CTC/7.5 mL in 46 of 213 patients (21.6%) before NT and in 22 of 207 patients (10.6%) after NT (P = 0.002). Twenty (15.0%) initially CTC-positive cases were CTC-negative after NT, whereas 11 (8.3%) cases were CTC-positive after NT, although no CTC could be found before NT. CTC detection did not correlate with primary tumor characteristics. Furthermore, there was no association between tumor response to NT and CTC detection. HER2-overexpressing CTC were observed in 14 of 58 CTC-positive patients (24.1%), including 8 patients with HER2-negative primary tumors and 3 patients after trastuzumab treatment. CTC scored HER2-negative or weakly HER2-positive before or after NT were present in 11 of 21 patients with HER2-positive primary tumors. HER2 overexpression on CTC was restricted to ductal carcinomas and associated with high tumor stage (P = 0.002).

CONCLUSION

CTC number was low in patients with primary breast cancer. The decrease in CTC incidence during treatment was not correlated with standard clinical characteristics and primary tumor response. Information on the HER2 status of CTC might be helpful for stratification and monitoring of HER2-directed therapies.

Abstract 3393: Identification of genes mediating early dissemination of tumor cells in breast cancer

The presence of disseminated tumor cells in bone marrow (BM) at primary breast cancer diagnosis is an independent prognostic factor. We have recently shown that there is a specific gene expression signature associated with BM micrometastasis in lung cancer patients (Wrage et al., CCR 2009). Our aim was therefore, to assess whether early metastatic spread of breast tumor cells into BM is also associated with a specific genetic signature. The gene expression profiles of primary early stage breast cancer patients (T1-2, N0, M0) with (n=15) and without (n=15) early tumor cell dissemination into BM were analyzed using the Affymetrix GeneChip platform. The BM status was assessed by immunostaining the BM samples with anti-cytokeratin antibody A45-B/B3. Gene expression data were normalized using gcrma and customized chip description files were used to re-map all probes to ENSEMBL transcripts. Rank sum test analysis was used to obtain transcripts that were significantly differentially expressed between BM positive and BM negative patients. Five publicly available breast cancer and three lung cancer expression data sets were used to correlate the findings with survival information.

When using false discovery rate of 0.2 and a p-value&lt;0.001, 28 genes were found significantly down regulated and only 4 genes significantly up regulated in the BM positive breast cancer group. The median fold-change between the BM positive and negative groups was 3.56. Quantitative RT-PCR verifications in primary tumors and metastases validated our findings.

The five large breast cancer data sets consisting of 1621 patients in total were used for in silico validations. Among the down-regulated genes 17 showed a significant association with survival in at least one data set, whereas 6 genes showed an association in at least two data sets. Among the four up-regulated genes a high expression of one gene was associated with shorter survival in two data sets whereas another gene was associated with shorter survival in one data set.

In summary, we could identify a set of potential key regulators of early hematogeneous spread of tumor cells. These potential new targets might be used to prevent metastatic relapse by eliminating DTC before the occurrence of overt metastases. Some of the identified genes are supposed to play a role only for the early steps of the metastatic cascade, i.e. dissemination, whereas others were shown also to be important for metastatic out-growth in distant organs and thus having a high impact on the survival of a patient.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3393.

Detect-Study: Comparison of Two Techniques for the Evaluation of the HER2 Expression on Circulating Tumor Cells in Metastatic Breast Cancer

Introduction:There is a growing body of evidence that the HER2 status can change during disease progression (Gancberg et al. 2003). However, the re-assessment of the HER2 status to evaluate the eligibility for HER2 targeted therapy by a tissue biopsy of the metastatic lesion may not always be feasible. In this context, determination of the HER2 status using CTCs might be a strategy with potential clinical application. So far, no large prospective studies were performed comparing different methods for CTCs detection and characterization. The aim of this trial was to determine the HER2 status of CTCs in metastatic breast cancer patients using the antibody based CellSearch©assay and the RT-PCR approach AdnaTest Breast Cancer and to assess the concordance rate between these two techniques. Both techniques are frequently used in clinical trials.Method:A total of 252 metastatic breast cancer patients from 9 different certified breast cancer centers (Düsseldorf, Erlangen, Essen, Freiburg, Hamburg, Heidelberg, Muenchen, Regensburg, Tuebingen) were enrolled in this prospective open trial from 01/2008 until 04/2009. HER2 status of CTCs was assessed using both the FDA approved CellSearch©Assay (Veridex, Warren, NJ, USA) and the AdnaTest Breast Cancer (Adnagen, Langenhagen, Germany) according to the manufacturers' instructions. A web based databank was designed for data management and online-documentation (www. detect-study.de). The study design was approved by the ethics' comittee (2007/B01).Results:Using the CellSearch©Assay, 133 of 252 (55%) metastatic patients had CTCs at the time of first diagnosis or disease progression. HER2 positivity was observed in 39% of CTC positive patients (52 of 133) but only 22 of these had initially a HER2 positive primary tumor. Eighty-eight of 225 (39%) patients were CTC positive using the AdnaTest Breast Cancer. The HER2 positivity rate was 47% (41 of 88). Eight of these patients had a HER2 positive primary tumor whereas 33 patients were initially HER2 negative or unknown. Summarizing the data, the rate of breast cancer patients with HER2 negative primary tumors but HER2 positive circulating tumor cells was 38% (32 of 61) and 48% (28 of 41) using the CellSearch Assay and the AdnaTest Breast Cancer, respectively. Considering only those patients who had CTCs on both tests (n=61), the concordance rate regarding HER2 expression was 51% (32 of 61).Conclusion:Based on CTCs the HER2 status can change during disease progression. However, using different techniques, disconcordant results were obtained. To prove the clinical value of these CTC assays and to implement the HER2 status of CTCs as a stratification parameter in future clinical trials, it will be mandatory to correlate clinical response to HER2 targetd therapy on each method in patients with HER2 positive CTCs.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3004.

Prospective Evaluation of Serum HER2 and HER2 Expression on Circulating Tumor Cells in Patients with Metastatic Breast Cancer within the DETECT Study

Background: Assessment of HER2 status at the time of metastatic disease might help to optimize treatment decisions in patients with no HER2 status determined at first diagnosis and could also be helpful since HER2 status may change during disease progression. In this context, determination of serum HER2 or the evaluation of HER2 status on circulating tumor cells (CTC) is of potential relevance especially for optimizing HER2-directed therapy. The aim of this study was therefore to determine the serum HER2 status and the HER2 status of CTC from corresponding patients.Methods: Blood samples were obtained in a prospective multicenter setting from 251 patients with metastatic breast cancer at the time of disease progression. Serum HER2 was determined using the commercial HER2 ELISA-kit (Oncogene Science). CTC were detected and HER2 expression was assessed with the CellSearch™ system (Veridex).Results: 119 of 251 (47%) metastatic patients had elevated serum HER2 levels above 15 ng/mL. Serum HER2 was elevated in 49 (66%) of 74 patients with HER2 positive primary tumors, in 57 of 148 (39%) with HER2 negative primary tumors and in 13 of 29 (45%) patients with unknown HER2 primary tumor status. CTC were detected in 133 of 243 evaluable patients (5 or more cells), in these HER2 overexpression on CTC (strong overexpression in at least one cell) was detected in 52 cases (39%). Only 20 of these patients had a HER2 positive primary tumor. In patients with HER2 positive CTC, serum levels were above the cut off in 34 of 52 (65%), while in those with HER2 negative CTC 44 of 81 (54%) showed elevated HER2 serum levels. Concordance between HER2 status of circulating tumor cells and elevated serum HER2 was seen in 71 of 133 patients (53%).Conclusions: Our study demonstrates with a prospective design that also in patients with initially negative HER2 tumor status elevated serum HER2 levels and/or HER2 positive CTC can be detected at the time of metastatic disease. This is of clinical relevance since these patients in current practice do not have access to HER2 targeted therapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3050.

Genomic profiles associated with early micrometastasis in lung cancer: relevance of 4q deletion

PURPOSE

Bone marrow is a common homing organ for early disseminated tumor cells (DTC) and their presence can predict the subsequent occurrence of overt metastasis and survival in lung cancer. It is still unclear whether the shedding of DTC from the primary tumor is a random process or a selective release driven by a specific genomic pattern.

EXPERIMENTAL DESIGN

DTCs were identified in bone marrow from lung cancer patients by an immunocytochemical cytokeratin assay. Genomic aberrations and expression profiles of the respective primary tumors were assessed by microarrays and fluorescence in situ hybridization analyses. The most significant results were validated on an independent set of primary lung tumors and brain metastases.

RESULTS

Combination of DNA copy number profiles (array comparative genomic hybridization) with gene expression profiles identified five chromosomal regions differentiating bone marrow-negative from bone marrow-positive patients (4q12-q32, 10p12-p11, 10q21-q22, 17q21, and 20q11-q13). Copy number changes of 4q12-q32 were the most prominent finding, containing the highest number of differentially expressed genes irrespective of chromosomal size (P=0.018). Fluorescence in situ hybridization analyses on further primary lung tumor samples confirmed the association between loss of 4q and bone marrow-positive status. In bone marrow-positive patients, 4q was frequently lost (37% versus 7%), whereas gains could be commonly found among bone marrow-negative patients (7% versus 17%). The same loss was also found to be common in brain metastases from both small and non-small cell lung cancer patients (39%).

CONCLUSIONS

Thus, our data indicate, for the first time, that early hematogenous dissemination of tumor cells might be driven by a specific pattern of genomic changes.

Regulation of estrogen-dependent transcription by the LIM cofactors CLIM and RLIM in breast cancer

Mammary oncogenesis is profoundly influenced by signaling pathways controlled by estrogen receptor alpha (ERalpha). Although it is known that ERalpha exerts its oncogenic effect by stimulating the proliferation of many human breast cancers through the activation of target genes, our knowledge of the underlying transcriptional mechanisms remains limited. Our published work has shown that the in vivo activity of LIM homeodomain transcription factors (LIM-HD) is critically regulated by cofactors of LIM-HD proteins (CLIM) and the ubiquitin ligase RING finger LIM domain-interacting protein (RLIM). Here, we identify CLIM and RLIM as novel ERalpha cofactors that colocalize and interact with ERalpha in primary human breast tumors. We show that both cofactors associate with estrogen-responsive promoters and regulate the expression of endogenous ERalpha target genes in breast cancer cells. Surprisingly, our results indicate opposing functions of LIM cofactors for ERalpha and LIM-HDs: whereas CLIM enhances transcriptional activity of LIM-HDs, it inhibits transcriptional activation mediated by ERalpha on most target genes in vivo. In turn, the ubiquitin ligase RLIM inhibits transcriptional activity of LIM-HDs but enhances transcriptional activation of endogenous ERalpha target genes. Results from a human breast cancer tissue microarray of 1,335 patients revealed a highly significant correlation of elevated CLIM levels to ER/progesterone receptor positivity and poor differentiation of tumors. Combined, these results indicate that LIM cofactors CLIM and RLIM regulate the biological activity of ERalpha during the development of human breast cancer.

Characterization of the HER2 status on circulating breast cancer cells

Abstract #5018

Background: Detection and characterization of circulating tumor cells (CTC) in the peripheral blood of breast cancer patients could help to guide treatment decisions before the onset of overt metastasis as well as in the setting of advanced disease. The HER2 oncogene is the most prominent therapeutic target in breast cancer and shedding of the extracellular domain of this receptor seems to contribute to constitutive activation of HER2. Here we developed a novel assay to detect shedding of the extracellular domain (ECD) of the HER2 oncogene on single CTC and applied this assay to the analysis of blood from metastatic breast cancer patients.&#x2028; Material and Methods: Using a new dual fluorescent CK19/HER2-EPISPOT assay, the shedding of HER2 ECD by CTC from 49 metastatic breast cancer patients was assessed. In parallel, using the CellSearch system, the number of CTC and their HER2 expression were determined on 42 samples from metastatic breast cancer patients. A subgroup (n=34) of these patients was analyzed with both methods. This work was performed in the context of the activities of the DETECT study group.&#x2028; Results: In the CK19/HER2-EPISPOT assay 24 of 49 (48.9%) patients had CTC (mean, 12.4; median, 5; range 1-141) and among these positive patients, 7 of 24 (29.2%) showed also HER2-secreting CTC (mean, 3.3; median, 2; range, 1-14). Using the CellSearch™ system, in 23/42 (54.8%) patients CTC were found (mean, 82; median, 13; range, 1-656). HER2 staining intensity was heterogeneous even among CTC from the same patient. Regarding the samples analyzed with both methods, we found that 23.5%, 50.0%, 50.0% and 76.5% of the patients were positive with both detection methods, the EPISPOT assay only, the CellSearch™ system only and one or the other method, respectively.&#x2028; Discussion: These findings demonstrate, for the first time, that (i) CTC can secrete HER2 and (ii) HER2 secretion is not closely linked to HER2 CellSearch™ status. Both assays (i.e., EPISPOT and CellSearch™) have a comparative sensitivity and appear to be complementary for the detection and characterization of the HER2-status of CTC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5018.

Circulating tumor cells and bone marrow micrometastasis

Sensitive immunocytochemical and molecular assays allow the detection of single circulating tumor cells (CTC) in the peripheral blood and disseminated tumor cells (DTC) in the bone marrow as a common and easily accessible homing organ for cells released by epithelial tumors of various origins. The results obtained thus far have provided direct evidence that tumor cell dissemination starts already early during tumor development and progression. Tumor cells are frequently detected in the blood and bone marrow of cancer patients without clinical or even histopathologic signs of metastasis. The detection of DTC and CTC yields important prognostic information and might help to tailor systemic therapies to the individual needs of a cancer patient. In the present review, we provide a critical review of (a) the current methods used for detection of CTC/DTC and (b) data on the molecular characterization of CTC/DTC with a particular emphasis on tumor dormancy, cancer stem cell theory, and novel targets for biological therapies; and we pinpoint to (c) critical issues that need to be addressed to establish CTC/DTC measurements in clinical practice.

Review: Biological relevance of disseminated tumor cells in cancer patients

The prognosis of cancer patients is largely determined by the occurrence of distant metastases. In patients with primary tumors, this relapse is mainly due to clinically occult micrometastasis present in secondary organs at primary diagnosis but not detectable even with high resolution imaging procedures. Sensitive and specific immunocytochemical and molecular assays enable the detection and characterization of disseminated tumor cells (DTC) at the single cell level in bone marrow (BM) as the common homing site of DTC and circulating tumor cells (CTC) in peripheral blood. Because of the high variability of results in DTC and CTC detection, there is an urgent need for standardized methods. In this review, we will focus on BM and present currently available methods for the detection and characterization of DTC. Furthermore, we will discuss data on the biology of DTC and the clinical relevance of DTC detection. While the prognostic impact of DTC in BM has clearly been shown for primary breast cancer patients, less is known about the clinical relevance of DTC in patients with other carcinomas. Current findings suggest that DTC are capable to survive chemotherapy and persist in a dormant nonproliferating state over years. To what extent these DTC have stem cell properties is subject of ongoing investigations. Further characterization is required to understand the biology of DTC and to identify new targets for improved risk prevention and tailoring of therapy. Our review will focus on breast, colon, lung, and prostate cancer as the main tumor entities in Europe and the United States.

Disseminated tumor cells in bone marrow and circulating tumor cells in blood of breast cancer patients: current state of detection and characterization

Despite the progress resulting from early detection and improved adjuvant therapy, the prognosis of breast cancer patients is still limited by the occurrence of distant metastases largely due to clinically occult micrometastases that remain undetected at primary diagnosis even by high-resolution imaging approaches. Recent research efforts have concentrated on the identification of additional parameters allowing individual risk assessment and stratification of patients for targeted therapies, since traditional prognostic factors are not sufficient to predict metastatic relapse and treatment decisions are still mainly based on statistical risk parameters. Highly sensitive and specific immunocytochemical and molecular assays now enable the detection and characterization of disseminated and circulating tumor cells (DTCs and CTCs, respectively) at the single cell level in bone marrow (BM) and peripheral blood, providing insights into the first crucial steps of the metastatic cascade. However, because of the still high variability of results in DTC/CTC detection, the necessity of standardized approaches will be discussed. A large number of studies showed that the presence of DTCs in BM has prognostic impact for primary breast cancer patients. DTCs are likely to escape from chemotherapy by maintaining a dormant nonproliferating state. There is also evidence for a stem cell-like phenotype of DTCs, probably contributing to the opportunity to escape from dormancy control and to start expansion to manifest metastases. Blood would also be an ideal source for the detection and monitoring of CTCs because of an easy noninvasive sampling procedure enabling repeated analyses. While prognostic significance of CTCs could be reliably demonstrated for metastatic breast cancer, studies to analyze the impact of CTCs in primary breast cancer patients and the potential to replace or supplement BM analysis are still ongoing. Furthermore, molecular characterization of CTCs might contribute to improving targeted and more individualized cancer therapies.

Identification of biologically active cancer cells in blood and bone marrow of cancer patients

1001

Background: Metastasis is the main cause of cancer-related death. Single disseminated tumor cells (DTC) can be detected by sensitive immunocytochemical and molecular technologies, but it is still unclear whether these cells are viable and biologically active. Methods: We applied a novel enzyme-linked immunospot assay (‘EPISPOT‘) that reveals a fingerprint of specific proteins secreted from single viable epithelial tumor cells. The membrane of ELISPOT plates were coated with monoclonal antibodies against the tumor-associated marker proteins mucin-1 (MUC1) for breast cancer and prostate-specific antigen (PSA) for prostate cancer. In addition, dual fluorescent EPISPOT assays were developed to characterize MUC1+ and PSA+ cells (i.e. CK19, FGF2 secretion). Results: Even in the absence of overt metastases (stage M0), the EPISPOT assay revealed viable tumor cells in the peripheral blood of 65% of prostate cancer patients (n=31) and the bone marrow of 54% of breast cancer patients (n=37). Respective samples from non-carcinoma controls were EPISPOT- negative, whereas 80 to 100% of samples from metastatic patients (stage M1, n=40) were positive. The number of EPISPOT-positive cells in M0-patients ranged from 2 to 197 in the blood of prostate cancer patients and 1 to 262 in the bone marrow of breast cancer patients, while M1- patients showed significantly higher counts (prostate cancer, 1–684; breast cancer, 4–813). Interestingly, subsets of MUC1- or PSA-secreting cells expressed a breast stem cell-like phenotype (MUC1-/CK19+) or secreted FGF-2 as factor relevant for the growth of DTC, respectively. Conclusions: A significant fraction of cancer patients harbor viable and biologically active tumor cells in their blood and bone marrow, even in the absence of overt metastases. The multiparameter EPISPOT assay helps to identify these putative metastatic precursor cells.

No significant financial relationships to disclose.

Prospective monitoring of circulating tumor cells in breast cancer patients treated with primary systemic therapy—A translational project of the German Breast Group study GeparQuattro

21085

Background: The impact of circulating tumor cells (CTC) in patients with primary breast cancer is still unclear. Primary systemic treatment (PST) allows the assessment of therapeutic efficacy in breast cancer patients without long follow-up periods. Here we present first results on the presence of CTC in peripheral blood of patients enrolled in the “GeparQuattro” study. Methods: This study incorporates three different chemotherapy approaches and additional Trastuzumab (Herceptin®) treatment for patients with HER-2/neu-positive tumors. Recruitment finished in November 2006 and not all patients have completed therapy yet. We used the CellSearch™ system to evaluate CTC before PST from 245 patients and after PST from 67 patients. CTC from 45 samples were also examined for HER-2/neu expression by immunocytochemistry in the CellSearch™ system. Results: Before PST we detected CTC in 54/245 patients (22%). CTC numbers in 7.5 mL blood ranged between 1 and 200 (mean 6.5). In 8 CTC-positive samples (3.3%) = 5 CTC were found. Her-2/neu-positive CTC were observed in 25/45 cases (55.6%). CTC could be detected in 7/67 patients (10.4%) after PST (1 or 2 CTC). Before and after PST blood was analyzed from 43 patients, 27 of them were CTC-negative at both time points. Ten initially CTC-positive cases were CTC-negative after PST whereas 6 cases were detected CTC-positive after PST although no CTC could be found before PST. Conclusions: With the CellSearch™ system CTC can be detected in non-metastatic breast cancer patients at primary diagnosis and also after PST. To our knowledge, this is the largest study evaluating the presence of CTC in this context. With the availability of response information from more patients, it will be possible to examine the correlation between the incidence of CTC and response as well as kinetics of HER-2/neu expression during Trastuzumab treatment.

[Table: see text]

Detection of Circulating Tumor Cells in Peripheral Blood of Patients with Metastatic Breast Cancer: A Validation Study of the CellSearch System

PURPOSE

The CellSearch system (Veridex, Warren, NJ) is designed to enrich and enumerate circulating tumor cells (CTCs) from peripheral blood. Here, we validated the analytic performance of this system for clinical use in patients with metastatic breast cancer.

EXPERIMENTAL DESIGN

This prospective multicenter study conducted at three independent laboratories involved samples from 92 patients with metastatic breast cancer. Intra- and inter-assay variability using controls containing defined numbers of cells (average, 50 and 1,000, respectively), cell stability based on varying storage and shipment conditions, recovery precision from samples spiked with 4 to 12 tumor cells, inter-instrument variability, and positivity of samples from metastatic breast cancer patients were tested.

RESULTS

Intra- and inter-assay precision for two sites were high: All eight positive controls analyzed in the same run and >95% of the run to run control values (n=299) were within the specified ranges. Recovery rate of spiked samples averaged between 80% and 82%. CTCs were detected in approximately 70% of metastatic breast cancer patients. CTC values of identical samples processed either immediately after blood drawing or after storage for 24, 48, or 72 h at room temperature or at 4 degrees C did not differ significantly. Shipment of samples had no influence on CTC values. When analyzing identical samples in different centers, inter-instrument accordance was high.

CONCLUSIONS

The CellSearch system enables the reliable detection of CTCs in blood and is suitable for the routine assessment of metastatic breast cancer patients in the clinical laboratory. Blood samples should be shipped at room temperature and CTC counts are stable for at least 72 h.

High incidence of EMMPRIN expression in human tumors

Extracellular matrix metalloproteinase inducer expressed by tumor cells stimulates peritumoral fibroblasts to produce matrix metalloproteinases, thus contributing to tumor invasion and metastasis. To assess its suitability as potential therapeutic target, the overall incidence of EMMPRIN expression in normal and neoplastic tissues was analyzed. EMMPRIN expression was detected immunohistochemically using monoclonal antibodies MEM-M6/1 and HIM6 and tissue microarrays with 2,348 and 608 tissue samples from 129 distinct tumor types and 76 different normal tissues, respectively. Expression and glycosylation state of EMMPRIN in human breast cancer cells were analyzed by Western blot analysis with monoclonal antibodies recognizing distinct carbohydrate structures and biochemical methods. EMMPRIN expression was found in 112 of 129 tumor entities analyzed with malignant tumors being EMMPRIN positive more frequently than benign tumors. A remarkable heterogeneity in EMMPRIN expression between tumor entities was observed. Among others, squamous-cell carcinomas (60-100%), pancreatic (87%), chromophobic kidney (83%), hepatocellular (83%) or medullary breast (83%) adenocarcinomas as well as glioblastoma multiforme (79%) presented with a particular high incidence of EMMPRIN expression. There were a limited number of EMMPRIN-positive normal cell types including proliferatively active and differentiating epithelial cells, germ cells, myocardial cells in the left heart ventricle or vascular endothelial cells of the brain. We could further demonstrate that breast cancer cells expressed EMMPRIN isoforms differing in the presence or absence of Lewis X glycan structures. Our results may assist in defining the suitability of EMMPRIN as therapeutic target and predicting negative side effects.

Detection of circulating lymphendothelial cells in patients with solid tumors

20010

Background: Bone marrow derived endothelial progenitor cells (ECPs) contribute to neoangiogenesis in cancer patients. Elevated numbers of circulating endothelial cells and EPCs can be detected in the peripheral blood of tumor patients. Recently, proliferating lymphatic vessels have been described in human cancers such as melanoma and head and neck tumors. Therefore, we investigated whether circulating lymphatic endothelial cells can be detected in cancer patients. Methods: We developed a sensitive immunocytochemical approach using a monoclonal antibody against the lymphendothelial specific hyaluronic receptor LYVE. After enrichment by Ficoll density gradient centrifugation, 7 × 10(5) peripheral blood mononuclear cells (PBMNCs) from 23 patients with metastatic cancer (6 gastrointestinal, 4 lung, 3 thymus, 3 thyroid, 1 mamma, 1 pancreas, 2 renal, 1 adrenal, 2 urothelial cancer, 1 PNET, 1 NET) and healthy individuals (n = 7) were spun onto glass slides. Two million PBMNs from each patient were stained for LYVE using the APAP technique. Isotype antibodies were used as controls. Cytospins were analyzed with the automated cellular imaging system (ACIS; ChromaVision Medical Systems). The method was validated with spiked blood samples. Results: Circulating LYVE+ lymphatic endothelial cells could be detected in 4 of 7 healthy subjects (57%) and in 16 of 23 patients (69%) with metastatic cancer. The mean number of lymphendothelial cells was significantly higher in cancer patients (15 cells/1 × 10(6) PBMNCs [range 0–276] vs. 1.0 cells/1 × 10(6) PBMNCs [range 0–2]). As a control, circulating tumor cells were enumerated after staining with a cytokeratin antibody (A45-B/B3). Circulating tumor cells could not be detected in healthy controls but in 13 of 23 of cancer patients (mean 1.4 cells/1 × 10(6) PBMNCs range [0–9]). Conclusion: Circulating lymphendothelial cells can be detected in patients with metastatic cancer and healthy subjects. Tumor patients have higher levels of circulating lymphendothelial cells than normal controls. These cells may participate in the generation of lymphatic vessels within tumor manifestations.

No significant financial relationships to disclose.

Changes in cytoskeletal protein composition indicative of an epithelial-mesenchymal transition in human micrometastatic and primary breast carcinoma cells

PURPOSE

The bone marrow is a frequent and clinically important homing site for early disseminated breast cancer cells. Here, we aimed to profile the protein expression of these cells using unique cell line models and to evaluate the prognostic relevance of candidate gene expression for breast cancer patients.

EXPERIMENTAL DESIGN

To identify expression patterns characteristic for micrometastatic cells, three different cell lines (BC-K1, BC-P1, and BC-S1) established by SV40 immortalization of cancer cells isolated from the bone marrow of patients with breast cancer were compared with MCF-7 breast cancer and SV40 immortalized normal breast ductal cells (MTSV-1.7) using two-dimensional gel electrophoresis followed by MALDI-ToF analysis. The prognostic significance and clinicopathologic associations of selected differentially expressed proteins were evaluated using high-density breast cancer tissue microarrays.

RESULTS

In contrast to MCF-7 and MTSV1-7 reference cell lines, all micrometastatic cancer cell lines displayed loss of epithelial cytokeratins (CK8, CK18, and CK19) and ectopic expression of vimentin commonly present in mesenchymal cells. Immunohistochemical analysis of 2,517 samples of breast cancer further showed that loss of cytokeratin and ectopic vimentin expression were significantly associated with a higher tumor grade, high mitotic index, and negative estrogen/progesterone-receptor status. Although in univariate analyses significantly related to clinical outcome, none of the cytokeratins analyzed were independently associated with either overall or cancer-specific survival.

CONCLUSIONS

Micrometastatic cancer cells exhibit marked changes in the expression pattern of cytoskeletal proteins indicative of an epithelial-mesenchymal transition. This phenotypical change could already be detected in primary tumors and is associated with the aggressive behavior of breast cancer cells in vivo.

Prognostic and predictive effects of immunohistochemical factors in high-risk primary breast cancer patients

PURPOSE

To analyze prognostic and predictive effects of immunohistochemical factors within a randomized study of high-dose versus standard-dose chemotherapy in high-risk breast cancer with >10 involved lymph nodes.

EXPERIMENTAL DESIGN

Histopathologic specimens in 188 of 302 patients were analyzed for Ki-67, p16, maspin, Bcl-2, Her2/neu, and p53.

RESULTS

In a univariate analysis after adjustment for therapy, tumor size, and estrogen receptor, Her2/neu positivity (P = 0.001) was a negative and Bcl2 positivity (P = 0.003) was a positive prognostic factor for event-free survival. In a multivariate analysis, Her2/neu positivity (hazard ratio, 3.68; 95% confidence interval, 2.01-6.73; P = 0.0001) had a negative influence on event-free survival, whereas p53 positivity (hazard ratio, 0.57; 95% confidence interval, 0.34-0.95; P = 0.03) and Bcl2 positivity (hazard ratio, 0.35; 95% confidence interval, 0.19-0.64; P = 0.0006) were associated with a better event-free survival. Analyzing the predictive effect of the immunohistochemical factors, an interaction between p53 and treatment could be shown (P = 0.005). The hazard ratio for high-dose chemotherapy versus standard chemotherapy is estimated as 2.3 (95% confidence interval, 0.67-7.92) in p53-negative patients and as 0.46 (95% confidence interval, 0.2-1.07) in p53-positive patients, which indicates a superiority of high-dose chemotherapy in p53-positive patients and an inferiority in p53-negative patients. No interactive effect could be shown for the other factors.

CONCLUSIONS

Her2/neu and Bcl-2 are prognostic but not predictive factors in patients with high-risk primary breast cancer; p53-positive patients might benefit more from high-dose chemotherapy than from standard chemotherapy, and p53-negative patients might benefit more from standard chemotherapy than from high-dose therapy.

Detection of human telomerase RNA in the tumour-surrounding mucosa of bladder carcinomas as a marker for premalignant transformation

OBJECTIVES

To investigate tumour tissue and non-malignant tumour-surrounding bladder mucosa (NTSBM) for expression of human telomerase RNA (hTR) as a possible marker for premalignant transformation of urothelial cells.

MATERIAL AND METHODS

From 67 patients with superficial transitional cell carcinoma (TCC), sections with representative tumour tissue and NTSBM were selected for evaluation. Sections with moderate or severe dysplasia were omitted from evaluation. hTR expression was detected with in situ hybridization using a 35S-UTP-labelled riboprobe, and analysed semiquantitatively by counting the hybridization signals.

RESULTS

In 45 of the 67 patients hTR expression was moderate or strong in tumour tissue, and in 20 hTR expression was moderate or strong in NTSBM. Moderate or strong hTR expression was detected in the NTSBM from 19 of 60 patients with pTa/pT1 tumours. Of the 56 patients who were treated conservatively, eight had tumour recurrence, of whom five had moderate or strong hTR expression in the TSBM, compared with only 14 of 48 patients without tumour recurrence.

CONCLUSION

Detecting hTR expression and the morphological distribution of hTR hybridization signals in NTSBM by in situ hybridization might indicate premalignant alterations involved in tumour recurrence.

Circulating tumor cells in breast cancer: correlation to bone marrow micrometastases, heterogeneous response to systemic therapy and low proliferative activity

PURPOSE

The incidence and biological characteristics of circulating tumor cells in the blood of patients with breast cancer were examined and subgroups were evaluated in the context of systemic treatment and the presence of disseminated tumor cells in bone marrow.

EXPERIMENTAL DESIGN

Circulating tumor cells were isolated from the peripheral blood of patients with breast cancer using a gradient system designed for the enrichment of circulating tumor cells (OncoQuick). Circulating tumor cells were identified with the anti-cytokeratin antibody, A45-B/B3. In subsets of patients, expression of the proliferation-associated Ki-67 antigen in circulating tumor cells and the concomitant presence of micrometastases in bone marrow were examined.

RESULTS

In patients with primary breast cancer (stage M(0)), circulating tumor cells were detected in 5 of 60 patients (8.3%) after surgery and before initiation of adjuvant chemotherapy; a positive correlation to the presence of disseminated tumor cells in bone marrow was observed (P = 0.030, n = 53). During the course of adjuvant chemotherapy, repeated analysis of 20 M(0) patients revealed the occurrence of circulating tumor cells in 7 of 16 patients that were initially negative. Patients with metastatic disease (stage M(1)) showed circulating tumor cells in 25 of 63 cases (39.7%, P < 0.0001 as compared with M(0) patients), and a positive finding was correlated with elevated concentrations of the serum tumor marker CA15.3 (P = 0.0093). Performing repeated analysis in a subgroup of 25 M(1) patients, circulating tumor cells were found more frequently in patients with progressive disease than in patients with stable disease or remission (87.5% versus 43.8% of patients with circulating tumor cells, respectively; P = 0.047). Independent of the disease-stage, none of the 47 patients examined for the proliferative status of their circulating tumor cells showed coexpression of Ki-67.

CONCLUSIONS

Circulating tumor cells seem to be nonproliferating cells that persist during chemotherapy. Circulating tumor cell detection is linked to disease progression and elevated tumor marker concentrations in patients with metastatic breast cancer.