Early metastasis of human solid tumours: expression of cell adhesion molecules

Loss and gain of cell surface molecules determines the mobilization, emigration and invasiveness of epithelial cancer cells. As a first approach to gain further insight into these processes, we have followed two strategies: (1) to identify tumour cells which have disseminated early from primary carcinomas and to obtain information about the phenotype and prognostic significance of these cells; and (2) to identify molecular changes occurring in primary tumour cells at the time they develop their metastatic potential. Our analyses indicate that changes in the adhesive properties of solid tumour cells, such as down-regulation of desmosomal proteins (e.g. plakoglobin) and neo-expression of ICAM-1 or MUC18, are important determinants of the metastatic capability of individual malignant cells. The expression pattern of these cell adhesion molecules during tumour progression appears to reflect a disturbance at the level of the molecular elements normally responsible for controlling their expression. The outlined current strategies for detection, characterization and antibody therapy of cancer micrometastasis can be applied to the secondary prevention of metastatic disease in patients with minimal residual cancer.

Detection of minimal residual disease (MRD) in peripheral blood of primary breast cancer patients: Translational research in the SUCCESS study

565

Background: Patients with detection of MRD in bone marrow are known to have an increased risk for recurrence and a poorer clinical outcome. However, peripheral blood would be the preferable compartment to monitor treatment efficacy due to increased feasibility. The translational research program of the German SUCCESS-trial was established to evaluate MRD in peripheral blood at 4 different time points during adjuvant systemic treatment of breast cancer patients. Here first results of the detection of MRD at primary diagnosis and after adjuvant chemotherapy will be presented. Patients and Methods: Cells were separated by Ficoll-Hypaque density- gradient centrifugation followed by labelling of epithelial cells with the anti-cytokeratine-antibody A45-B/B3 (directed against cytokeratines 8, 18 and 19) and immunohistochemically staining with neu-fuchsin. All preparations were screened by two independent persons. Results: 328 breast cancer patients were analyzed at primary diagnosis. Among those, 133 patients returned for a 2nd blood sampling after completion of adjuvant chemotherapy. Most of the tumors were small (43% pT1, 51% pT2, 4% pT3, 1% pT4) but of intermdediate or unfavourable grade, (G1 7%, G2 48%, G3 45%). 66% of the patients were node-positive (34% pN0, 38% pN1, 20% pN2, 8% pN3) and a positive hormone receptor status was seen in 71%. In 22% the Her2-status was positive. MRD in peripheral blood was found in 31% of all patients before and in 9% after chemotherapy. The mean number of detected cells was 2 (range 1- 9). In 87,2 % of the patients who showed MRD at the first measurement no MRD was detected after chemotherapy. 16% of patients without detection of MRD at primary diagnosis showed MRD after chemotherapy. Neither tumor size (p= 0.624), lymph node metastases (p= 0.450), histopathological grading (p= 0.168), hormone receptor status (p= 0.270) or Her2/neu status of the primary tumor (p= 0.893) correlated with the presence of MRD. Conclusions: The detection of MRD in peripheral blood can be widely used and is suitable for repeated measurements. Further follow-up will show, if this method can be used for risk stratification and monitoring of treatment efficacy in adjuvant breast cancer.

No significant financial relationships to disclose.

Circulating tumor cells (CTCs) in peripheral blood of primary breast cancer patients

10595

Background: Detection of CTCs has been shown to predict decreased PFS and OAS in metastatic breast cancer, whereas only limited data has been published in the adjuvant setting. We evaluate the role of CTCs in peripheral blood at primary diagnosis and during adjuvant chemotherapy, endocrine and bisphophonate treatment within the SUCCESS-Trial (n=3,658 pts). Methods: We analyzed 23ml of peripheral blood from 1767 N+ and high risk N- primary breast cancer pts before systemic treatment. 852 of these pts have undergone follow-up blood sampling after completion of chemotherapy. The presence of CTCs was assessed with the CellSearchSystem (Veridex, Warren, USA). Briefly, after immunomagnetic enrichment with an anti-Epcam-antibody, cells were labelled with anti-cytokeratin (8,18,19) and anti-CD45 antibodies to distinguish epithelial cells and leukocytes. Results: 10% of pts with a blood sampling before systemic treatment (n=170) showed >1CTC before the start of systemic treatment (mean 13, range 2–827). While we found 2 CTCs in 5% of pts, 3% had 3–5 CTCs and 1% 6–10 and >10 CTCs each. The presence of CTCs did not correlate with tumor size (p=.07), grading (p=.30), hormonal status (p=.54) or Her2-Status of the primary tumor (p=.26). However, we observed a significant correlation with the presence of lymph node metastases (p=.015). None of 24 healthy individuals showed more than 1 CTC. Among those 852 pts with follow-up blood sampling after the completion of cytostatic treatment, 11% were CTC positive before starting systemic treatment (mean 7, range 2–166), while 7% of patients presented with >1CTC after completion of chemotherapy (mean 6, range 2–84). Of those, initially CTC positive, 10% remained positive (n=9) and 90% had a negative CTC test after chemotherapy (n=82). Of those initially CTC negative, 93% remained negative (n=711), whereas 7% returned with a positive CTC test (n=50) (p=.24). Conclusions: Our data show good feasibility of this highly standardized and easily applicable approach for the detection of CTCs in a large number of primary breast cancer patients. In a considerable number of patients, persistent CTCs can be detected after completion of cytostatic treatment. Whether this finding is prognostically relevant will have to been shown with longer follow-up of the SUCCESS-trial.

No significant financial relationships to disclose.

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]

A European interlaboratory testing of three well-known procedures for immunocytochemical detection of epithelial cells in bone marrow. Results from analysis of normal bone marrow

BACKGROUND

This investigation intended to study the unspecific background to be expected in normal bone marrow (BM), comparing three well recognized protocols for immunocytochemical detection of disseminated carcinoma cells. The interlaboratory variation in screening and evaluation of stained cells was analyzed and different screening methods were compared.

METHODS

BM mononuclear cells (BM MNC) from 48 normal BMs were immunostained in parallel by three participating laboratories. The protocols, based on three different anti-cytokeratin antibodies, have all been in common use for detection of disseminated carcinoma cells: the A45-B/B3 protocol (Hamburg), the CK2 protocol (Augsburg) and the AE1AE3 protocol (Oslo). For all protocols, the immunostained cells were visualized by the same alkaline-phosphatase (AP) detection system (APAAP) followed by detection of the cells by manual screening and by two different automated screening systems (ACIS from Chromavision and MDS1 from Applied Imaging). Detected AP-visualized cells were morphologically classified into unambiguous hematopoietic (Uhc) and questionable cells (Qc, potentially interpreted as tumor cells).

RESULTS

Seven of 48 BMs (15%) harbored > or = 1 AP-visualized cell(s) among 1 x 10(6) BM MNC, both for the A45-B/B3- and for the AE1AE3 protocol, while for CK2 a higher proportion of BMs (21 BMs; 44%) harbored AP-visualized cells (P < 0.01, McNemar's test). The number of Qc was, for all protocols, 1 log lower than the total number of AP-visualized cells. On average, the frequency of Qc was 0.04, 0.08, and 0.02 per 10(6) BM MNC with A45-B/B3, CK2 and AE1AE3, respectively, and the number of Qc-positive BMs 1, 4, and 1. The MDS1 screening sensitivity was similar to manual screening, while ACIS detected fewer cells (P < 0.001, McNemar's test).

CONCLUSIONS

All protocols resulted in AP-visualization of occasional hematopoietic cells. However, morphological classification brings the specificity to a satisfactory high level. Approximately 10% of AP-visualized cells were categorized "questionable". The CK2 protocol turned out less specific than the A45-B/B3 and AE1AE3 protocols.

Incidence of circulating tumor cells (CTCs) in peripheral blood of breast cancer patients at primary diagnosis—A potential tool for risk stratification

20053

Background: In metastatic breast cancer, CTCs have been proven an independent predictor for progression-free and overall survival (Cristofanilli, NEJM 2004). Therefore, we evaluated the role of CTCs in peripheral blood of breast cancer patients at primary diagnosis and during adjuvant systemic treatment within the Success-Trial (n = 3,658 pts). First results of the incidence of CTCs prior to chemotherapy will be presented here. Methods: The CellSearchSystem (Veridex) was used for isolation and enumeration of CTCs from 23 ml of peripheral blood. Briefly, after immunomagnetic enrichment with an anti-Epcam-antibody, cells were labelled with anti-cytokeratin (8,18,19) and anti-CD45 antibodies to distinguish epithelial cells and leukocytes. Patients had been accrued between September and December 2005. Results: We analyzed 124 breast cancer patients at the time of primary diagnosis. The majority of patients presented with small tumors (41% T1, 55% T2, 4% T3), and 32% were node-negative (45% N1, 14% N2, 9% N3). While a positive hormone receptor status was observed in 74% of patients and 31% were her2/neu positive, most tumors showed an intermediate or unfavourable grading (2% G1, 98% G2–3). In this patient group, 32% of patients (n = 40) presented with ≥1CTC in peripheral blood. In patients with the detection of CTCs, the mean number of cells was 5 (range 1–38). In 11 healthy individuals we found 1 CTC in one blood sample. The presence of CTCs did not correlated with tumor size (p = .39), presence of lymph node metastases (p = .25), histopathological grading (p = .33), hormone receptor status (p = .56) or her2/neu status of the primary tumor (p = .14). Conclusions: The isolation of CTCs from peripheral blood of primary breast cancer patients is feasible and might prove as an easy applicable and convenient technique to give further insight into the spread of the disease. The Success-Trial will investigate, whether CTCs can be used for risk stratification to more tailored treatment approaches and for the monitoring of treatment efficacy in individual patients.

[Table: see text]

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.

Persistence of disseminated tumor cells (DTC) in bone marrow (BM) of breast cancer patients predicts increased risk for relapse—Results of pooled European data

10083

Background: The prognostic significance of DTC in the BM of breast cancer patients at the time of primary diagnosis has recently been confirmed by a large pooled analysis. If the persistence of DTC after adjuvant therapy confers a similar risk for relapse, there might be an indication for secondary adjuvant treatment. Methods: We analyzed BM aspirates of 697 patients from academic breast cancer units in Oslo (n=356), Munich (n=228) and Tuebingen (n=113) during recurrence-free follow-up at a median interval of 32.4 months (standard deviation [std] 19.4 mon) after primary diagnosis of breast cancer pT1–4, pN0–3 pM0. Carcinoma cells were detected using a standardized immunoassay with the monoclonal antibodies A45-B/B3 (Munich, Tuebingen), or AE1 and AE3 (Oslo), directed against cytokeratin (CK). Patients were followed for a median of 54.2 months (std 24.5 mon) after primary diagnosis. Results: Persistent DTC in the BM were detected in 15.6% of the patients (n=109). The Kaplan-Meier estimate for mean distant relapse-free survival estimate was 155.6 mon (142.4 - 168.9 95%CI) in patients with negative and 102.3 mon (93.6 - 111.0, 95% CI, p< .0001, log rank test) in patients with positive BM status. Patients without evidence of persistent DTC had a significantly longer overall survival (164.4 [155.6 - 173.3]), than patients with positive BM status (101.7 mon [89.4 - 113.9], p< .0001). In multivariate Cox regression analysis, allowing for bone marrow status, tumor size, nodal status, histopathological grading and hormone receptor status, DTC was of higher independent prognostic significance for subsequent reduced breast cancer specific survival (RR 5.9, 2.8 - 12.8, 95% CI, p< .0001), than nodal status at time of primary diagnosis (RR 1.2, 1.0 - 1.3, 95% CI, p=.014). Conclusion: Evidence of persistent DTC in breast cancer patients indicates an increased risk for subsequent relapse, and may serve for monitoring in future clinical trials. Such trials might investigate the benefit of individualized secondary adjuvant treatment or extended adjuvant therapy of patients with DTC.

No significant financial relationships to disclose.

Presence of bone marrow micrometastasis (BMM) in breast cancer patients predicts a poor-prognosis pattern of first distant metastasis: Results from the pooled analysis

567

Background: As a putative surrogate marker of ubiquitous distant metastasis, which is assessable both at initial diagnosis of breast cancer and during adjuvant therapy, BMM would be a valuable end-point marker for adjuvant clinical trials. Methods: Based on individual pt data of 4,686 breast cancer pts with a 10-year follow-up (median, 62 months), we analyzed distant disease-free survival (DDFS) of BMM+/BMM− pts, and looked specifically into sites of first metastatic relapse, expressed as bone metastasis-free (BFS), visceral metastasis-free (VFS), and multiple metastasis-free survival (MFS; i.e., simultaneous diagnosis of bone and visceral metastases). We performed Kaplan-Meier analysis and computed incidence rates (IR)/ incidence rate ratios (IRR) for the occurrence of metastasis at different sites. Results: BMM were detected in 1,432 (30.6%) of pts overall and significantly more often in pts with subsequent diagnosis of distant metastasis as compared to those who survived without metastases (48.5% vs. 26.0%, P<0.001). BMM+ pts had a significantly shorter DDFS than BMM- pts (IRR 2.36; 95%CI, 2.07–2.69; P<0.001). This was also true when we analyzed either bone (IRR 2.73; 95%CI, 2.27–3.29; P<0.001) or visceral metastases only (IRR, 2.48; 95%CI, 2.11–2.91; P<0.001). Among 952 pts with occurrence of distant metastasis, IR of such an event was 1.28-fold (95%CI, 1.12–1.46; P<0.001) higher in BMM+ pts than in BMM- pts. Among 462 BMM+ pts (but not among those 490 BMM- pts), IRs for MFS were significantly increased as compared to both VFS (IRR 1.72; 95%CI, 1.36–2.18; P<0.001) and BFS (IRR 1.85; 95%CI 1.21–2.06; P=0.001). IR for BFS of BMM+ patients (1.08; 95%CI 0.87–1.34) was not significantly increased over VFS. Conclusion: Our data provide conclusive evidence that presence of BMM predicts an early onset and a poor prognosis pattern of overt distant metastasis. With the similar likelihood of the occurrence of subsequent metastasis in bone and at visceral sites, BMM appears to be a marker of generalized tumor cell spread.

No significant financial relationships to disclose.

[Minimal residual disease in breast cancer: detection and clinical relevance]

Hematogenous distant metastasis is the leading cause of cancer-related death in breast cancer and other solid tumours. By applying sensitive immunocytochemical and molecular assays disseminated tumour cells (DTC) in bone marrow (BM) can be detected in 20-40% of cancer patients without any clinical or even histopathological signs of metastasis. The detection and characterisation of DTC in BM may lead to a better understanding of the biology initiating metastatic spread in cancer patients and will eventually contribute to the development of more effective strategies to eliminate DTC. In this review, we will therefore discuss the detection, characterisation and clinical relevance of DTC.

BM micrometastases and circulating tumor cells in breast cancer patients: where have we been, where are we now and where does the future lie?

Over the past 15 years early tumor cell dissemination has been detected in patients with breast cancer using sensitive immunocytochemical and molecular assays based on the use of MAb and PCR, respectively. Clinical studies involving more than 4,000 breast cancer patients have now demonstrated that the presence of disseminated tumor cells in BM identified with immuncytochemical assays at primary diagnosis is a strong and independent prognostic factor. The published studies for the detection of disseminated tumor cells in BM fulfill the highest level of evidence as prognostic markers in primary breast cancer. In addition, various assays for the detection of circulating tumor cells in the peripheral blood have been developed recently and some studies suggest a potential clinical relevance of this parameter as a prognostic and predictive factor. Comparative analyzes indicate that the prognostic information derived from BM and blood screening seems to be complementary and not redundant. Advanced methods for molecular characterization of single tumor cells and the surrounding environment have been developed lately, and this approach allows new insights into the metastatic cascade and characterization of targets for therapeutic approaches. Taken together, these findings provide the basis for the implementation of disseminated tumor cells in BM or blood as markers for stratification and assessment of therapies in prospective clinical trials. The valuable information derived from these trials should help to improve future treatment of breast cancer patients.