Prognostic relevance of disseminated tumor cells in the bone marrow and biological factors of 265 primary breast carcinomas

Circulating and disseminated tumor cells: diagnostic tools and therapeutic targets in motion

Enumeration of circulating tumor cells (CTCs) in peripheral blood with the gold standard CellSearchTM has proven prognostic value for tumor recurrence and progression of metastatic disease. Therefore, the further molecular characterization of isolated CTCs might have clinical relevance as liquid biopsy for therapeutic decision-making and to monitor disease progression. The direct analysis of systemic cancer appears particularly important in view of the known disparity in expression of therapeutic targets as well as epithelial-to-mesenchymal transition (EMT)-based heterogeneity between primary and systemic tumor cells, which all substantially complicate monitoring and therapeutic targeting at present. Since CTCs are the potential precursor cells of metastasis, their in-depth molecular profiling should also provide a useful resource for target discovery. The present review will discuss the use of systemically spread cancer cells as liquid biopsy and focus on potential target antigens.

Mechanisms governing metastatic dormancy and reactivation

Many cancer patients suffer from metastatic relapse several years after they have undergone radical surgery. Early cancer cell dissemination followed by a protracted period of dormancy potentially explains this prevalent clinical behavior. Increasing evidence suggests that the metastasis-initiating cells are cancer stem cells or revert to this functional state upon infiltrating a target organ. Their entry into dormancy and subsequent reactivation are governed by intrinsic programs and by contextual cues, which resemble those regulating the self-renewal capability of adult stem cells. In addition, metastatic cells undergoing reactivation are nursed by specialized extracellular matrix niches, which support positive signals, such as Wnt and Notch, and attenuate negative signals, such as BMP. In spite of significant remaining uncertainties, these findings provide a framework to understand the logic of metastatic dormancy and reactivation and open new avenues for therapeutic intervention.

Correlation between Ki67 and breast cancer prognosis

BACKGROUND

Ki67 is an immunohistochemical proliferation marker in many types of cancer and has been widely studied among breast cancer patients mostly through retrospective studies.

METHODS

The MEDLINE/PubMed database was searched for publications with the medical subject heading 'Ki 67' and the key words 'breast', 'cancer', and 'prognosis'. We restricted our search to articles published until 2012.

RESULTS

In this review, we included 78 articles and abstracts that were accessible and available in English. An effort to further explain the role of Ki67 in the prognosis of breast cancer has been made.

CONCLUSIONS

The debate on the prognostic role of Ki67 in breast cancer is still open, although most of the studies have established a relation between Ki67 and overall and disease-free survival. Further research should be made in order to establish Ki67 as a standard prognostic marker in breast cancer.

Bisphosphonates: prevention of bone metastases in breast cancer

Disease recurrence and distant metastases remain challenging for patients with breast cancer despite advances in early diagnosis, surgical expertise, and adjuvant therapy. Bone is the most common site for breast cancer metastasis, and the bone microenvironment plays a crucial role in harboring disseminated tumor cells (DTCs), a putative source of late relapse in and outside bone. Therefore, agents that affect bone metabolism might not only prevent the development of bone lesions but also provide meaningful reductions in the risk of relapse both in bone and beyond. Bisphosphonates bind to mineralized bone surfaces and are ingested by osteoclasts, wherein they inhibit osteolysis, thereby preventing the release of growth factors from the bone matrix. Therefore, the bone microenvironment becomes less conducive to survival and growth of DTCs and bone lesion formation. Recent trials of zoledronic acid in the adjuvant setting in breast cancer have demonstrated reduced disease recurrence in bone and other sites in premenopausal and postmenopausal women with early breast cancer. Based on the proven effect of bone protection during adjuvant endocrine therapy, new treatment guidelines recommend the routine use of bisphosphonates to prevent bone loss during adjuvant therapy, which may likely become the standard practice.

Circulating tumour cells in peripheral blood: potential impact on breast cancer outcome

INTRODUCTION

In breast cancer, the metastatic process may involve the dissemination of circulating tumour cells (CTCs) through the blood and lymphatic system prior to the colonisation of distant organs. Here we demonstrate the predictive capacity of CTCs for detecting risk of death in breast cancer patients during established time intervals.

METHODS

CTCs were identified by immunocytochemical methods following isolation by selective immunomagnetic cell separation of cytokeratin-positive cells. Serial blood samples from 65 patients were collected at roughly monthly intervals for up to 50 months. Follow-up was conducted at different intervals: 1-5, >5-12, >12-24 and >24-50 months.

RESULTS

Both presence and number of CTCs were correlated to risk of death: patients with CTCs at any time during follow-up had a higher risk of death (p=0.035) than patients without CTCs. Furthermore, during the first 5 months of therapy, patients with >5 CTCs had a higher risk of death than patients with <5 CTCs (p=0.002).

CONCLUSIONS

Our results show that the persistence of CTCs after chemotherapy, particularly during the first 5 months, could define a group of patients with a high risk of relapse.

Could targeting bone delay cancer progression? Potential mechanisms of action of bisphosphonates

Although dissemination may occur early in the course of many cancers, the development of overt metastases depends upon a variety of factors inherent to the cancer cells and the tissue(s) they colonize. The time lag between initial dissemination and established metastases could be several years, during which period the bone marrow may provide an unwitting sanctuary for disseminated tumor cells (DTCs). Survival in a dormant state within the bone marrow may help DTCs weather the effects of anticancer therapies and seed posttreatment relapses. The importance of the bone marrow for facilitating DTC survival may vary depending on the type of cancer and mechanisms of tumor cell dissemination. By altering the bone microenvironment, bisphosphonates may reduce DTC viability. Moreover, some bisphosphonates have demonstrated multiple anticancer activities. These multiple mechanisms may help explain the improvement in disease outcomes with the use of zoledronic acid in malignancies like breast cancer and multiple myeloma.

Bones, breasts, and bisphosphonates: rationale for the use of zoledronic acid in advanced and early breast cancer

Bisphosphonates inhibit osteoclast-mediated bone resorption, thereby inhibiting the release of growth factors necessary to promote cancer cell growth, differentiation, and tumor formation in bone. These agents have demonstrated efficacy for delaying the onset and reducing the incidence of skeletal-related events in the advanced breast cancer setting, and have been shown to prevent cancer therapy-induced bone loss in the early breast cancer setting. Emerging clinical data indicate that the role of bisphosphonates in advanced and early breast cancer is evolving. Retrospective analyses and recent clinical trial data show that zoledronic acid may improve outcomes in some patients with breast cancer. Data from ABCSG-12 and ZO-FAST suggest that zoledronic acid may improve disease-free survival in the adjuvant breast cancer setting in postmenopausal women or women with endocrine therapy-induced menopause, and recent data from a predefined subset of the AZURE trial added to the anticancer story. However, the overall negative AZURE trial also raises questions about the role of bisphosphonates as an anticancer agent in patients with breast cancer. Overall, these data suggest that the addition of zoledronic acid to established anticancer regimens may have potential anticancer benefits in specific patient populations, although more studies are required to define its role.

Detection and clinical relevance of early disseminated breast cancer cells depend on their cytokeratin expression pattern

The factors determining the clinical relevance of disseminated tumor cells (DTC) in breast cancer patients are largely unknown. Here we compared the specificity and clinical performance of two antibodies frequently used for DTC detection. Reactivities of antibodies A45-B/B3 (A45) and AE1/AE3 (AE) for selected cytokeratins (CK) were assessed by 2-DE Western Blot analysis. Using these antibodies bone marrow aspirates from 391 breast cancer patients (M(0), pT1-3, pN0-3) were screened for the presence of DTC. To obtain prognostic information, patients were followed up over a median of 83 months for time to relapse and 99 months for time to death. Among the analyzed CK, AE detected CK5, CK7, CK8, and CK19, whereas A45 recognized CK7 and CK18. In total, 24 of 391 patients (6.1%) were DTC-positive for A45, and 41 (10.5%) for AE. Although concordance between the two antibodies was 84.4%, overlap among positive cases was only 3.2%. DTC-positivity with AE and A45 was more frequent in patients of higher nodal status (P=0.019 and P=0.036, respectively). Nearly all patients with A45-positive DTC had hormone receptor-positive tumors (23/24), while detection of AE-positive DTC was more frequent among hormone receptor negative patients (P=0.006). Survival analyses of all patients revealed shorter distant disease-free survival (P=0.039) for patients with A45-positive DTC, whereas the prognostic relevance of AE-positive DTC was restricted to node-positive patients. The clinical utility of immunocytochemical (ICC) DTC detection depends on the anti-CK antibody used, which may reflect the complex CK composition of DTC.

Clinical relevance associated to the analysis of circulating tumour cells in patients with solid tumours

The distant growth of tumour cells escaping from primary tumours, a process termed metastasis, represents the leading cause of death among patients affected by malignant neoplasias from breast and colon. During the metastasis process, cancer cells liberated from primary tumour tissue, also termed circulating tumour cells (CTCs), travel through the circulatory and/or lymphatic systems to reach distant organs. The early detection and the genotypic and phenotypic characterisation of such CTCs could represent a powerful diagnostic tool of the disease, and could also be considered an important predictive and prognostic marker of disease progression and treatment response. In this article we discuss the potential relevance in the clinic of monitoring CTCs from patients suffering from solid epithelial tumours, with emphasis on the impact of such analyses as a predictive marker for treatment response.

Topoisomerase IIalpha expression rather than gene amplification predicts responsiveness of adjuvant anthracycline-based chemotherapy in women with primary breast cancer

INTRODUCTION

Adjuvant anthracycline-based chemotherapy (AbCTX) is a standard treatment for patients with primary breast cancer. Its main target is topoisomerase IIalpha (TopIIa), a nuclear protein which is important for DNA replication and mitosis. We propose that the overexpression of the TopIIa protein or amplification of the TopIIa gene may be useful in predicting increased responsiveness towards AbCTX.

METHODS

Tumor tissues of 118 patients who received adjuvant AbCTX were examined by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) for TopIIa and HER2. For IHC, the primary antibodies 485 (Dako) and NCL-TOPOIIA (Novocastra) were used. FISH analysis was performed with the SPEC HER2/CEP 17 Dual Color Probe (Zytovision) and LSI TOP 2A Spectrum Orange/CEP 17 Spectrum Green probe (Abbott). TopIIa IHC was evaluated by the immunoreactive score (IRS). FISH amplification was stated at an HER2-TopIIa/CEP 17 ratio > or = 2, deletion of TopIIa at a ratio <0.8.

RESULTS

The median age of the patient population was 50 years (range 23-77), 76 (64%) had tumors >2 cm in size, 98 (85%) were nodal positive, and 72 (66%) estrogen-receptor positive. Chemotherapy regimes consisted of epirubicin-cyclophosphamide (EC 40 pts), EC-CMF (18 pts), FAC/FEC (33 pts), anthracycline-taxane combinations (23 pts) and others (4 pts). After IHC, it was found that 19% of the tumors were positive for HER2 (3+) and the median IRS for TopIIa staining was 2 (49% positive); 28 (24%) tumors showed HER2 amplification, therefrom 20/22 (91%) within the HER2 3+ group. TopIIa gene was amplified in 17 cases (16%) and deletion was seen in 6 (5%) tumors. Of all cases with HER2 gene amplification, 14 (50%) cases of TopIIa co-amplification and one case of deletion were seen. Looking at histological parameters, TopIIa IHC correlated with nodal status (P = 0.018) and high grading (G3) (P = 0.047). After a median follow-up of 42 months (range 1-242), a significant prognostic factor for local recurrence was HER2 positivity (IHC P = 0.013 and FISH P = 0.023). Thirty-two patients developed metastasis (27%), which was correlated with HER2 FISH positivity (P = 0.024) and, as a trend, Top IIa IHC negativity (P = 0.094); 25 (21%) patients died from the disease. Negative prognostic parameters were the lack of estrogen-receptor expression (P = 0.008), lymphangiosis (P = 0.02), and TopIIa IHC negativity (P = 0.03).

CONCLUSION

In this cohort of patients, HER2 positivity indicated higher rates of local and distant recurrence. In contrast, TopIIa IHC positivity predicted lower risk of metastases and death, thus being a positive-predictive factor for the responsiveness to AbCTX. TopIIa gene amplification did not add predictive information. Therefore, we conclude that TopIIa protein expression might rather be the target of anthracyclines independent from gene copy number.

Diagnostic accuracy of small breast epithelial mucin mRNA as a marker for bone marrow micrometastasis in breast cancer: a pilot study

BACKGROUND

Detection of isolated tumour cells (ITC) in the blood or minimal deposits in distant organs such as bone marrow (BM) could be important to identify breast cancer patients at high risk of relapse or disease progression. PCR amplification of tissue or tumour selective mRNA is the most powerful analytical tool for detection of this micrometastasis. We have evaluated for the first time, the diagnostic accuracy of small breast epithelial mucin (SBEM) as a potential marker for BM micrometastasis in breast cancer.

METHODS

A nested RT-PCR assay for detection of SBEM mRNA was compared with immunocytochemistry (ICC) with anticytokeratin AE1/AE3 antibody in paired samples obtained from the BM of breast cancer patients. Associations of SBEM mRNA detection in BM and clinical and pathological parameters were evaluated. SBEM mRNA status and time to breast cancer progression were analysed using Kaplan-Meyer curves.

RESULTS

Fifty stages I-IV breast cancer female patients were prospectively included in our study. SBEM specific transcript was found in BM in 26% of the patients. Detection rate was similar to the percentage of patients with ITCs detected using ICC (24%). SBEM mRNA in BM aspirates were significantly associated with presence of clinically active disease, including locally advanced and metastatic patients (47%, P = 0.021) and tumours with positive hormonal receptors (36.7%, P = 0.035). In addition association with Her2/neu over-expression (44.4%, P = 0.051) and low proliferating tumours (36%, P = 0.067) were close to significant levels. When we analysed time to breast cancer progression adjusting for grade or hormone receptor status, presence of SBEM mRNA in BM defines distinct prognostic groups.

CONCLUSIONS

SBEM might represent a suitable marker for molecular detection of ITCs in BM in breast cancer patients. Analysis of prognostic value for SBEM mRNA-based assay should take into account the heterogeneity and different molecular subtypes of breast cancer.

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.

Bone Marrow Micrometastases in Breast Cancer Patients: A Long-Term Follow-up Study

In 125 early breast cancer patients who underwent multiple bone marrow aspirates, there was no significant difference in terms of disease-free and overall survival after a median follow-up of 163 months between the patients with or without micrometastasis at the time of primary surgery. However, when the time-dependent evolution of the bone marrow aspirates was taken into account, some evidence for a longer disease-free and overall survival was found for the patients with negative bone marrow

Bone Marrow Micrometastases in Breast Cancer Patients: A Long-Term Follow-up Study

In 125 early breast cancer patients who underwent multiple bone marrow aspirates, there was no significant difference in terms of disease-free and overall survival after a median follow-up of 163 months between the patients with or without micrometastasis at the time of primary surgery. However, when the time-dependent evolution of the bone marrow aspirates was taken into account, some evidence for a longer disease-free and overall survival was found for the patients with negative bone marrow.

An update on prognosis in breast cancer patients with extensive axillary disease

Lymph node (LN) status is the most important factor in predicting survival in breast cancer. Historically, patients with 10 or more positive LN have been thought to have a particularly poor prognosis, which has in the past been used to alter therapeutic recommendations. Studies conducted both prior to and after the use of anthracycline-based chemotherapy demonstrate poor survival. We hypothesized that the current survival rate is considerably higher. All patients with breast cancer treated at our institution between July 1991 and December 2005 with at least 10 positive axillary LN were identified. A multivariate Cox proportional hazards model was performed using age, number of positive nodes, and primary tumor characteristics. Of 55 patients identified, two were excluded for incomplete follow-up information. The median patient age was 53; median follow-up was 5-years. The overall 5-year survival rate was 71.9%. On univariate analysis estrogen receptor (ER) status (p = 0.0001), progesterone receptor status (p = 0.004), use of adjuvant chemotherapy (p = 0.01), T-stage (p = 0.03), and adjuvant hormonal therapy (p = 0.002) were statistically significant for survival. In the multivariate analysis, only ER status and the use of adjuvant chemotherapy remained significant for survival. ER negativity conferred a hazard ratio of 12.6 (95% confidence interval: 3.7-43.2) and the use of adjuvant chemotherapy had a hazard ratio of 0.14 (95% confidence interval: 0.04-0.46). In our study, patients with at least 10 positive axillary LN had a 5-year survival of 71.9% which may be due to the improvements in local and systemic therapy.

Excision repair cross-complementation group 1 predicts progression-free and overall survival in non-small cell lung cancer patients treated with platinum-based chemotherapy

Expression of excision repair cross-complementation group 1 (ERCC1), p53, or thioredoxin (TRX) is reported to be correlated with resistance to platinum-based drugs. The authors evaluated whether ERCC1, p53, or TRX expression could predict progression-free and/or overall survival in relapsed non-small cell lung cancer (NSCLC) patients treated with platinum-based chemotherapy. Immunohistochemistry was used to examine the expression of these three proteins in resected lung tumor samples obtained from 67 patients treated with platinum-based chemotherapy against recurrent tumors after curative resection. Immunostaining for ERCC1, p53, and TRX was positive in 29, 35, and 24 patients, respectively. Patients negative for ERCC1 had a significantly longer median progression-free (44 vs 26 weeks, P = 0.0075) and overall (73 vs 44 weeks, P = 0.0006) survival than those positive for ERCC1. Patients negative for p53 expression had a significantly longer median overall (70 vs 62 weeks, P = 0.0289), but not progression-free (37.5 vs 36 weeks, P = 0.2465), survival than those positive for p53 expression. From multivariate analysis, negative ERCC1 expression (hazard ratio [HR] = 1.3740, P = 0.0147) was a significantly favorable factor for progression-free survival, and negative ERCC1 expression (HR = 1.6533, P = 0.0018) and better performance status (HR = 1.9117, P = 0.0017) were significantly favorable factors for overall survival. This retrospective study indicates that immunostaining for ERCC1 may be useful for predicting survival in NSCLC patients receiving platinum-based chemotherapy against recurrent tumors after curative resection and can provide critical information for planning personalized chemotherapy.

Prognostic impact of Thomsen-Friedenreich tumor antigen and disseminated tumor cells in the bone marrow of breast cancer patients

PURPOSE

The Thomsen-Friedenreich antigen (TF, CD176) is a specific oncofetal carbohydrate epitope (Gal beta1-3GalNAc alpha-O-Ser/Thr) expressed on the surface of various carcinomas. It mediates endothelium adhesion and formation of metastases. As it also causes immune response, its prognostic impact is indeterminate. The presence of disseminated tumor cells in the bone marrow of breast cancer patients (DTC-BM) indicates worse prognosis. We examined the expression of TF in primary breast cancer tissue of 265 patients with known BM status at the time of first diagnosis.

METHODS

BM aspiration, cytospin preparation and immunocytochemical staining with the anti-Cytokeratin antibody A45 B/B3 was done following a standardised protocol. TF expression was examined immunohistochemically on Tissue Micro Arrays (TMA) with the anti-TF antibody A78-G/A7. Evaluation was done using the immunoreactive score (IRS).

RESULTS

Median IRS for TF expression was 2 (0-12). 68 of 265 patients (25.7%) showed DTC-BM with a median of 2/2 x 10(6) cells (1-1500). There was no correlation between TF expression and DTC-BM. After a median follow up of 60.1 months (7-119), the detection of DTC-BM showed prognostic significance for overall survival (OS, p = 0.034), whereas TF positivity (IRS > 2) indicated prolonged disease-free (p = 0.01), distant disease-free (p = 0.005), and overall survival (p = 0.005).

DISCUSSION

Patients with TF-positive tumors had a significantly better prognosis. Dissemination routes, TF-mediated metastasis formation, and the immunogeneity of TF might determine the prognostic impact of TF expression in different tumor entities. Further characterisation of primary tumors and DTC-BM could help to improve the biological understanding of metastases and develop targeted therapies.