Cytokeratin 20 is not a reliable molecular marker for occult breast cancer cell detection in hematological tissues

Detection of mammaglogin A in blood from breast cancer patients, before and after treatment, using a one-tube nested PCR protocol. Association with the absence of tumor estrogen receptors

OBJECTIVE

A one-tube nested RT-PCR protocol was set up and used to detect mammaglobin A (MGA) expression in blood samples from breast cancer patients. The correlation of MGA detection with prognostic factors was analyzed.

DESIGN AND METHODS

Total RNA from nucleated blood cells was extracted from 65 breast cancer patients (before surgery and after the treatments) and 18 healthy subjects and used to detect MGA expression by a modified nested RT-PCR.

RESULTS

MGA expression was detected in 38.4% of patients before surgery, and in 50% and 36.8% of post-treatment samples from patients that expressed MGA or were MGA negative before surgery, respectively. MGA detection was associated with the absence of tumor estrogen receptors (p=0.004).

CONCLUSIONS

MGA detection by the modified nested RT-PCR is a specific marker for circulating tumor cells in patients with breast carcinoma and a negative prognostic factor for the disease.

The melanoma-associated antigen-A3, -A4 genes: relation to the risk and clinicopathological parameters in breast cancer patients

This study aimed to evaluate the clinical reliability and accuracy of two MAGE transcripts (MAGE-A3, MAGE-A4 mRNA) in the peripheral blood (PB) of patients with breast cancer (BC), and to evaluate their potential limits and utility to detect BC. We aimed also to analyze their relation to clinicopathological characteristics of the tumor. This study is a prospective, controlled, double-blinded study conducted on 100 BC women and 100 age-matched control women. There were 52 patients with localized breast mass with no evidence of nodal affection or distant metastases and 48 patients suffering from metastatic BC. MAGE-A3 and MAGE-A4 mRNA in the PB were assayed using reverse transcriptase-polymerase chain reaction (RT-PCR). None of the control women was positive for either MAGE-A3, MAGE-A4. In BC women, positivity for MAGE-A3 in PB was observed in 37 patients (37%), and MAGE-A4 positivity was observed in 11 patients (11%); with 100% specificity for both transcripts. The presence of MAGE-A3 was significantly associated with nodal status (P = 0.009), tumor size (P = 0.009), and American Joint Committee on Cancer stage (P = 0.009), whereas MAGE-A4 positivity was significantly associated with histological grade (P = 0.020). RT-PCR assays of MAGE-A3 and MAGE-A4 in the PB of BC patients may have prognostic and predictive implications, and they are promising specific tumor markers of BC.

Small breast epithelial mucin (SBEM) has the potential to be a marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer

To investigate the potential role of small breast epithelial mucin (SBEM) as a marker for detecting hematogenous micrometastasis in breast cancer and explore its clinical significance in neoadjuvant chemotherapy. SBEM protein expression in 82 tissue specimens of primary breast cancer was detected using immunohistochemistry (IHC), and SBEM expression in peripheral blood (PB) samples of 109 primary breast cancer patients (94 cases at stage I-III, 15 cases at stage IV) was detected by flow cytometry (FCM) and reverse transcription polymerase chain reaction (RT-PCR). Moreover, SBEM mRNA expression was monitored by quantification real-time PCR (QPCR) before and after 3 cycles' neoadjuvant chemotherapy. SBEM expression correlated with tumor node metastasis (TNM) staging and lymph node metastasis at both mRNA and protein levels. SBEM expression in PB of breast cancer patients was markedly higher than that of healthy donors and other cancer patients. SBEM was found expressed in PB of 50 cases among 94 cases at stage I-III and expressed in PB of 11 cases among 15 cases at stage IV. After 3 cycles' neoadjuvant chemotherapy, SBEM expression levels were significantly down-regulated in up to 58% breast cancer patients. SBEM has the potential to be a specific marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer.

Mammaglobin and maspin transcripts in blood may reflect disease progression and the effect of therapy in breast cancer

Detection of residual tumor cells in the circulation can provide prognostic as well as therapeutic information and help in identifying patients at high risk for developing metastases. Maspin and mammaglobin are two molecules that are specifically associated with breast cancer. We looked for mammaglobin and maspin transcripts in the peripheral blood of patients with breast cancer and evaluated their utility as a marker of the response to therapy. Maspin and mammaglobin transcripts were analyzed in 85 breast-cancer patients by nested RT-PCR, prior to and after treatment. Before therapy, 10 patients were found positive for mammaglobin and 20 patients were positive for maspin. In four patients, both transcripts were detected. Immediately following treatment, only one patient was still positive for mammaglobin while maspin transcripts persisted in three patients. Disease progression was observed mainly in patients in whom maspin transcripts were not detectable. Molecular detection of circulating tumor cells during therapy based on analysis for mammaglobin and maspin transcripts is an easy and practical method that can be applied to follow-up patients. We suggest that detection of mammaglobin mRNA is useful to determine the effect of therapy while maspin transcripts may indicate more aggressive disease.

Circulating tumor cells (CTCs): detection methods and their clinical relevance in breast cancer

The enumeration of circulating tumor cells has long been regarded as an attractive diagnostic tool, as circulating tumor cells are thought to reflect aggressiveness of the tumor and may assist in therapeutic decisions in patients with solid malignancies. However, implementation of this assay into clinical routine has been cumbersome, as a validated test was not available until recently. Circulating tumor cells are rare events which can be detected specifically only by using a combination of surface and intracellular markers, and only recently a number of technical advances have made their reliable detection possible. Most of these new techniques rely on a combination of an enrichment and a detection step. This review addresses the assays that have been described so far in the literature, including the enrichment and detection steps and the markers used in these assays. We have focused on breast cancer as most clinical studies on CTC detection so far have been done in these patients.

DETECTION OF DISSEMINATED TUMOR CELLS IN PERIPHERAL BLOOD

Metastases are the major cause of cancer-related deaths in patients with solid epithelial malignancies, such as breast, colorectal and prostate carcinomas. Hematogenous spreading of tumor cells from a primary tumor can be considered as a crucial step in the metastasis cascade leading eventually to the formation of clinically manifest metastases. Consequently, as shown in recent studies, the detection of disseminated tumor cells in peripheral blood might be of clinical relevance with respect to individual patient prognosis and staging or monitoring of therapy. However, the rarity of disseminated tumor cells in peripheral blood renders the application of sensitive techniques mandatory for their detection. The emergence of highly sophisticated reverse transciptase-polymerase chain reaction (RT-PCR) assays, combining a preanalytical enrichment step with the assessment of multiple molecular tumor markers expressed in disseminated tumor cells, provides a powerful tool in detecting disseminated tumor cells with high sensitivity and specificity. This review will discuss currently used tumor markers as well as experimental means to enhance the sensitivity and specificity of RT-PCR assays to detect disseminated tumor cells in the peripheral blood of patients with breast, colorectal, and prostate cancers, and their clinical relevance assessed in recent studies.

Detection of Survivin-expressing circulating cancer cells in the peripheral blood of breast cancer patients by a RT-PCR ELISA

Survivin mRNA expression was detected in 69.2%-93.8% of primary breast carcinomas, but is rarely expressed in normal breast tissues and hematopoietic cells. The objective of this study was to investigate the significance that the detection of Survinin-expressing circulating breast cancer cells in the peripheral blood has on clinical outcomes. The detection method was based on a RT-PCR ELISA technique developed in our laboratory. Sixty-seven breast cancer patients in various stages and 135 normal healthy women were investigated. Survivin-expressing circulating cancer cells were detected in the peripheral blood samples from 34 (50.7%) out of 67 breast cancer patients, but not in the healthy women that were used as controls. The presence of Survivin-expressing circulating breast cancer cells was found to be significantly associated with various clinicopathological parameters such as vessel infiltration, histological grade, tumor size, nodal status, ER/PgR status, Her-2 status and clinical stages of the disease (P < 0.01). During a follow-up period of 36 months, 9 out of 11 (81.8%) breast cancer patients that had a positive Survivin-expressing at the time of the initial assay test suffered a relapse of the disease, whereas recurrence was only found in 2 out of 6 (33.3%) breast cancer patients that had a negative Survivin-expression. Thus, the detection of circulating cancer cells expressing Survivin mRNA could provide valuable information for the prediction of metastasis and recurrence of breast cancer.

The detection of circulating breast cancer cells in blood

At present, sampling of the lymph nodes or bone marrow for the detection of regions of metastatic disease in patients with breast cancer can only be undertaken at the time of initial diagnosis and surgery. However, the sampling of these tissues and the methods used are inaccurate, time consuming, and cannot be used for easy routine screening to determine disease recurrence and response to treatment. Because of the problems encountered with current methods and tissues sampled at the time of breast cancer diagnosis, this review discusses the urgent requirement for and potential development of a quick, simple, and accurate diagnostic test utilising the haematogenous system, a source of circulating tumour cells in patients with breast cancer, and highly sensitive molecular biological techniques, such as reverse transcription polymerase chain reaction. In addition, this review also highlights potential problems that may be encountered and should be avoided when devising such a test.

M34 Actin Regulatory Protein Is a Sensitive Diagnostic Marker for Early- and Late-Stage Mammary Carcinomas

PURPOSE

At present, there is no available molecular marker that reliably detects the earliest stages of epithelial transformation in the majority of patients affected with incipient breast carcinoma. Here we introduce M34 protein, a mammalian actin filament regulatory protein, as a highly sensitive and easily detected positive cellular marker for both early and late stages of breast carcinoma.

EXPERIMENTAL DESIGN

In this study, 24 human lactation duct neoplasms from postmenopausal women, including fibroadenoma, ductal carcinoma in situ, intraductal lobular papilloma, and metastatic adenocarcinoma, were analyzed for the presence of M34 protein by histochemical staining of paraffin and fresh-frozen sections.

RESULTS

All 24 neoplasias tested positive for M34, whereas none of the 4 normal breast tissues stained for the protein. M34 identification was strongly positive for transformed epithelium in all tumor types tested. Twelve precancerous lesions of fibroadenoma (n = 4), intraductal papilloma (n = 4), and incipient ductal carcinoma in situ (n = 4) all showed high levels of M34 staining, suggesting that precancerous tumors, as well as the earliest stages of mammary carcinoma, can be sensitively detected. Furthermore, anti-M34 antibody selectively stained all 12 advanced-stage metastatic adenocarcinoma cell masses and micrometastases in axillary lymph nodes tested. Single-cell micrometastases embedded in connective tissue or lymph node parenchyma could be clearly resolved by M34 with horseradish peroxidase staining. Lymphocytes, normal ductal endothelium, and vascular endothelial cells were M34-negative, as were muscle, nerve, and adipose tissues. Low-level M34 staining was detected in connective tissue fibroblasts, macrophages, and neutrophils.

CONCLUSIONS

To our knowledge, no previously reported markers have shown high sensitivity of detection for both the earliest and most advanced stages of breast carcinoma. Consequently, M34 appears uniquely suited for diagnosis of the earliest stages of lactation duct transformation as well as for advanced-stage mammary carcinoma metastases in surgical margins and axillary lymph nodes.

Identification of carcinoma cells in peripheral blood samples of patients with advanced breast carcinoma using RT-PCR amplification of CK7 and MUC1

We have undertaken a pilot study to attempt to identify circulating carcinoma cells in a series of patients with advanced breast carcinoma, using reverse transcription-polymerase chain reaction (RT-PCR) to amplify mRNA of epithelial specific antigens. Using this method to amplify mRNA of MUC1 and cytokeratin 7 (CK7) the sensitivity of the technique was demonstrated by means of diluted concentrations of "spiked MCF7" cells in whole blood, showing a detection limit of 1 in 10(6) (CK7) and 1 in 10(5) (MUC1). Positive results were obtained from the peripheral blood of all nine female patients with advanced breast cancer for CK7 and eight of the nine patients for MUC1. CK7 was however detected in five of 11 healthy controls (eight females, three males) and MUC1 in one of the 11 controls. None of the control group were positive for both CK7 and MUC1, in contrast to eight of the nine patients with advanced breast carcinoma who were positive for both markers. The RT-PCR method thus appears sufficiently sensitive to identify circulating tumour cells in peripheral blood samples from patients with advanced breast carcinoma. However a high proportion of false-positive results was seen in the control population. More extensive investigation is required before the technique is likely to be of benefit clinically.

Human mammaglobin RT-PCR assay for detection of occult breast cancer cells in hematopoietic products

BACKGROUND

The aim of this study was: (i) to evaluate the sensitivity and specificity of mammaglobin as a reverse transcriptase polymerase chain reaction (RT-PCR) marker of breast cancer cells; (ii) to determine the incidence of tumor cell contamination of hematopoietic samples from patients with breast cancer.

MATERIALS AND METHODS

A nested RT-PCR assay for mammaglobin was developed. Sensitivity was determined by serial dilution assays with breast cancer cell lines, human breast cancers and normal breast tissue. Specificity was evaluated in hematopoietic samples from healthy volunteers and patients with hematological malignancies or solid tumors other than breast cancer.

RESULTS

The mammaglobin transcript was detected in all 15 breast cancers, one benign breast tumor and five normal breast tissues studied, as well as in three breast cancer cell lines, in dilutions as low as 10(-8). The transcript was not detected in any of 47 peripheral blood samples, 15 bone marrow aspirates and 28 peripheral blood progenitor cell samples from the three control populations. Mammaglobin mRNA was detected in 19 of 78 peripheral blood samples from patients with breast cancer starting systemic chemotherapy, as well as in five of 30 repeat samples collected before the fourth cycle of treatment. The transcript was also present in six of seven bone marrow aspirates from patients with metastatic disease, two of five with loco-regional disease, but not in the aspirate of two patients with thrombocytopenia and a previous history of breast cancer.

CONCLUSIONS

Human mammaglobin mRNA is a sensitive and specific marker of breast cancer cells and should be further studied as a molecular marker of tumor cell contamination of hematopoietic tissues.