hMAM Expression Research Articles

Modulation of Molecular Biomarker Expression in Response to Chemotherapy in Invasive Ductal Carcinoma.

Breast cancer (BC) has varied morphological and biological features and is classified based on molecular and morphological examinations. Molecular classification of BC is based on biological gene-expression profiling. In this study, biomarker modulation was assessed during BC treatment in 30 previously untreated patients. Heterogeneity among patients was pathologically diagnosed and classified into luminal and basal-like immunohistochemical profiles based on estrogen, progesterone, and human epidermal growth factor receptor (ER/PR/HER2) status. Marker heterogeneity was compared with mRNA biomarker expression in patients with BC before and after therapy. Reverse transcription-polymerase chain reaction was performed for molecular characterization. Expression and modulation of biological markers, CK19, hMAM, CEA, MUC, Myc, Ki-67, HER2/neu, ErbB2, and ER, were assessed after treatment, where the expression of the biomarkers CK19, Ki-67, Myc, and CEA was noted to be significantly decreased. Marker expression modulation was determined according to different stages and pathological characteristics of patients; coexpression of three markers (CK19, Ki-67, and Myc) was specifically modulated after therapy. In the histopathologically classified basal-like group, two markers (CK19 and Ki-67) were downregulated and could be considered as diagnostic biomarkers. In conclusion, pathological characteristics and marker variation levels can be evaluated to decide a personalized treatment for patients.

Anti-hMAM monoclonal antibodies evaluated in breast and non-breast tissues for differential diagnosis implication.

Human mammaglobin (hMAM) is a breast tissue-specific marker that may have potency for the diagnosis of breast cancer. However, there is a lack of commercialization of anti-hMAM antibody made in China. Immunoreactivities of 2 self-made monoclonal anti-hMAM antibodies, MEF521 and MDA822, were evaluated by immunohistochemistry staining and compared with imported monoclonal antibody ab81611. A total of 48 cases of primary breast cancers, 36 cases of benign or normal breast tissues, 52 cases of lymph nodes or organ metastases from breast cancer, and 90 cases of non-breast primary carcinoma tissues were analyzed. All 3 anti-hMAM antibodies showed high positive expression of hMAM in primary breast cancers, benign, and normal breast tissues. The positive ratio for MEF521 (33.3%) or MDA822 (44.4%) was much higher than that of ab81611 (16.7%) in lymph node metastasis from breast cancer (p = 0.038). There was no correlation between hMAM expression and clinicopathologic features of breast cancer in the 3 groups of antibodies. In 90 cases of non-breast primary carcinoma tissues, no hMAM-positive ones were observed in the MEF521 or MDA822 group, but 48 (53.3%) in the ab81611 group were positive, indicating that breast tissue specificity of the 2 self-made anti-hMAM monoclonal antibodies much higher than that of ab81611 (p<0.001). Our results showed that MDA822 and MEF521 are more specific to breast cancer as measured by means of immunohistochemistry. Therefore, the 2 self-made anti-hMAM antibodies may have good prospects for clinical application in the differential diagnosis of breast tumor and breast cancer metastases.

Upregulation of Human Mammaglobin Reduces Migration and Invasion of Breast Cancer Cells

Little is known about the biological role of human mammaglobin (hMAM) that is considered as a promising marker for breast cancer. Here, we investigated hMAM's role related to migration and invasion of human breast cancer cells (hBCC). Compared to normal cells, hBCC have high MAM mRNA expression levels. Of the hBCC tested, MAM mRNA expression levels were higher in noninvasive than in invasive cells. Overexpression of hMAM in breast cancer cells decreased migration and invasion, whereas knockdown of hMAM increased both. Taken together, these results suggest that metastasis of hBCC could be controlled by hMAM expression levels.

Expression of hMAM, VEGF-C and VEGFR-3 in breast cancer tissues and its relation with prognosis

Expression of hMAM, VEGF-C and VEGFR-3 in breast cancer tissues and its relation with prognosis

Clinical Relevance of Human Mammaglobin mRNA in Pleural Effusion from Patients Undergoing Thoracoscopy: A Pilot Study

human mammaglobin (hMAM) expression has been reported in pleural effusions (PE). The aim of this study was to assess the clinical relevance of hMAM mRNA in PE from patients who underwent thoracoscopy. A total of 288 patients with PE were studied, 155 of which were diagnosed with malignant and 133 with non-malignant diseases by thoracoscopy. Cells from PE were analyzed by nested hMAM RT-PCR. Statistical analyses were performed to evaluate the diagnostic performance parameters (DPP), the association between hMAM expression and benign or malignant status and the relative risk of cancer for patients with negative thoracoscopy showing hMAM positivity. hMAM mRNA was found in 68/288 (23.6%) PE samples of which 51 were from the 155 patients diagnosed with malignant diseases and 17 were from the 133 patients diagnosed with non-malignant diseases. A significant correlation between hMAM expression and malignancy was found (OR=3.04) and the DPP were as follows: sensitivity=32.9%, specificity=87.2%, accuracy=58.0%, positive predictive value=75.0% and negative predictive value=52.7%. Among the patients with negative thoracoscopy (n=133), 5/17 (29.4%) hMAM-positive patients had or developed a tumor during the 18-month follow up period, as compared to 10/116 (8.6%) hMAM-negative patients (relative risk of 4.6 for developing a malignancy). These findings suggest a possible application of hMAM RT-PCR detection in PE as to identify a false-negative thoracoscopy in non-specific pleuritis.

Plasma human mammaglobin mRNA associated with poor outcome in patients with breast cancer

Different treatment outcomes and prognoses in patients with breast cancer can be observed with similar clinical predictors; this is because the biology of breast cancer is complex and heterogenous, involving multiple unknown contributing factors. We looked for plasma human mammaglobin (hMAM) mRNA by RT-PCR in 82 Korean patients with breast cancer to determine if there is an association between the presence of plasma hMAM mRNA in these patients and known prognostic factors. The prognostic usefulness of detection of plasma hMAM mRNA expression in these patients was also evaluated by determining overall survival and event-free survival. A significant difference was observed in the rate of positivity of plasma hMAM mRNA between the early stages of cancer (stages I-II, 23.4%) and advanced stages (stages III-IV, 82.9%). The expression rates of estrogen receptor, progesterone receptor, and HER-2/neu in the breast tissue of these patients, by immunohistochemistry, were 69.5, 75.6, and 20.7%, respectively. In the univariate analysis, plasma hMAM expression was significantly correlated with high histological and nuclear grades, nodal metastasis, and negative estrogen receptor and progesterone receptor status. Patients negative for plasma hMAM mRNA had significantly higher rates of event-free survival compared to the patients positive for plasma hMAM mRNA. However, no significant association with overall survival was observed for expression of plasma hMAM mRNA (P = 0.16). Qualitative detection of plasma hMAM mRNA appears to be associated with unfavorable prognostic factors and lower rates of event-free survival in patients with breast cancer.

Expression of human mammaglobin as a marker of bone marrow micrometastasis in breast cancer

The aim of the present study was to detect the expression of human mammaglobin (hMAM) mRNA in the bone marrow (BM) of patients with breast cancer and determine the relationship between micrometastasis and clinicopathological parameters as well as selected molecular markers and breast cancer prognosis. The expression of hMAM mRNA in the BM of patients with breast cancer was determined by RT-PCR. The expression of ER, PR and Cath-D in cancer tissues was detected by immunohistochemistry. A positive expression rate for hMAM of 38.2% in 102 patients with stage I-III breast cancer was found. The expression of hMAM was higher in patients with T(2-3) (>2 cm) tumors than in those with T(1) tumors (≤2 cm) (χ(2)=19.20, P=0.001) and in patients with stage II or III tumors than in patients with stage I tumors (χ(2)=15.101, P=0.001). The expression of hMAM in the BM of breast cancer patients categorized as grade 1 was lower than that in those of grade 2 or 3 (χ(2)=8.522, P=0.014), and hMAM expression was related to the pathological type of tumor (χ(2)=6.892, P=0.032) and the degree of axillary lymph node metastasis (χ(2)=14.050, P=0.001). The expression of hMAM in BM was much higher in patients with ER(-) or ER(+) tumors than in those with ER(++ or +++) (χ(2)=11.800, P=0.003), and those with PR (χ(2)=8.759, P=0.013). hMAM expression in BM was also significantly positively correlated with Cath-D expression (χ(2)=6.623, P=0.036). However, no correlation was found between hMAM expression and patient age (χ(2)=1.056, P=0.304). There was a strong correlation between patients with positive expression of hMAM in the BM and the presence of distant metastases (P=0.009). In conclusion, micrometastasis in the BM correlates with certain clinical pathological parameters and several tumor markers. Patients with positive expression of hMAM in the BM have a greater chance of distant metastasis and poor prognosis. The detection of micrometastasis may be one of the most advantageous markers for predicting the prognosis of breast cancer.

Evaluation of the prognostic significance of human mammaglobin expression in pleural effusion from patients with negative thoracoscopy.

10534 Background: It has been reported that application of the RT-PCR test for human mammaglobin (hMAM) may provide diagnostic information to evaluate the neoplastic origin of pleural effusion (PE). Our main goal was to assess the value of hMAM RT-PCR as an adjunctive test to thoracoscopic biopsy which represents the conventional gold standard in PE diagnosis. Methods: This study included 288 patients who underwent thoracoscopy. Histological analysis of pleural biopsies showed malignant diseases (MT) in 155/288 (53.8%) patients and non-malignant diseases (NMT) in 133/288 (46.2%) patients. The cells obtained from PE were analyzed by a nested RT-PCR protocol for hMAM mRNA gene detection. We evaluated the association between hMAM expression and MT vs NMT status by the diagnostic odds ratio (DOR). The diagnostic performance parameters of sensitivity (Se), specificity (Sp), accuracy (Ac), predictive positive value (PPV), predictive negative value (PNV) were also analysed. In addition, the relative risk of cancer in negative thoracoscopy patients showing hMAM expression in PE was evaluated by multivariate logistic regression analysis. Results: hMAM transcript was found in 68/288 (23.6%) of the total PE. Among them, 51/155 (Se=32.9%) positive cases were from MT and 17/133 (1-Sp=12.8) were from NMT. Statistical analysis showed significant correlation between hMAM expression and MT (DOR value of 3.04). The diagnostic performance parameters of hMAM detection were as follows: Sp=87.2.%, Ac=58.0%, PPV=75.0% and NPV=52.7%. The 18 month follow up of negative thoracoscopy patients showed that 5/17 (29,4%) of hMAM positive PE had a tumour in contrast to 10/126 (7.9%) of hMAM negative PE with a relative risk of 4.6 for developing malignancy (p=0.023). Conclusions: Our findings suggest a prognostic value of PE hMAM in non-specific pleuritis and may point out a false-negative thoracoscopy.

Diagnosis and Origin Determination of Malignant Pleural Effusions Through the Use of the Breast Cancer Marker Human Mammaglobin

As was reported that human mammaglobin (hMAM) may be expressed in malignant pleural effusions (PEs), we investigated the relevance of hMAM reverse-transcriptase polymerase chain reaction (RT-PCR) for their diagnosis and determination of primary origin. Two hundred and twenty-eight malignant (132 male, 96 female) and 185 benign (132 male, 53 female) PEs were investigated. Statistical analyses evaluated the diagnostic performance parameters in all PEs and in cytologically negative malignant PEs, the association between hMAM and benign or malignant status by the direct index of correlation [diagnostic odds ratio (DOR)], chi test, and P value (P). In addition, the discriminative diagnostic power of hMAM expression, independently in breast cancer, lung cancer (LC), malignant mesothelioma (MM), and other cancers was evaluated. In the entire patient population, hMAM was detected in 45.6% and 5.4% of malignant and benign PEs, respectively, in the male group in 41.7% and 4.5% and in the female group in 51.0% and 7.5% of malignant and benign PEs, respectively. A statistically significant correlation between hMAM and malignancy was found in the entire population (DOR=14.68, P<0.001) and in the male (DOR=15.00, P<0.001) or female (DOR=12.77, P<0.001) groups. hMAM RT-PCR increased the diagnostic rate of malignant PEs as it allowed us to detect as malignant 32.1% of cytologically negative PEs. In female patients the positivity of hMAM indicated with higher probability (50.8%) the origin of PEs from breast cancer but lower probability from LC (17%), MM (9.4%), or other cancers (15.1%), whereas in male patients it indicated with similar probability (about 40%) the origin from LC or MM. Our results suggest that hMAM RT-PCR may provide information both in the diagnosis of PE and in the search for the primary site of neoplasia, either in male or female patients.

The role of bone marrow micrometastasis in breast cancer in judging prognosis.

Objective To investigate the relationship between bone marrow micrometastasis of patients with breast cancer and clinical pathological parameters, some molecular markers as well as prognosis.Methods The expression of hMAM mRNA in BM of patients with breast cancer was detected by RT-PCR.The expressions of ER, PR in cancer tissues were detected by immunohistochemical SP method. Results About 38.2 % positive expression rate of hMAM mRNA in 102 patients with stage Ⅰ -Ⅳ breast cancer was found.The expression of hMAM increased more in patients with T2-3 (＞2 cm) tumors than T1 (≤2 cm) (P =0.001)and with stage Ⅱ ,Ⅲ than stage Ⅰ (P =0.001). The expression of hMAM in the BM of breast cancer with grade I was lower than that of grade Ⅱ or Ⅲ (P =0.014). The expression of hMAM in the BM was related to the pathological type (P =0.032) and the axillary lymph node metastasis (P =0.001). The expressions of hMAM in BM were much higher with ER negative in breast cancer tissues (P ＜0.05). There was a correlation between patients with positive expression of hMAM in BM and distant metastasis (P =0.009). Conclusion The micrometastasis in BM is correlated with some clinical pathological parameters and some tumor markers. The patients with positive expression of hMAM in BM have more chances with distant metastasis and poor prognosis. The detection of micrometastasis may be as one of targets to predict the prognosis of breast cancer. Key words: Breast neoplasms; Bone marrow micrometastasis; Human mammaglobin; Biological factor; Reverse transcriptase polymerase chain reaction; Prognosis

Application of suspension array assay to detect marker genes expression of circulating tumor cells for early prediction of breast cancer metastasis

To develop a suspension array assay to detect the expression of multiple genes in the circulating breast cancer cells simultaneously so as to identify the marker genes for human breast cancer metastasis. Peripheral blood samples were obtained from 73 breast cancer patients, including 31 breast cancer metastasis patients, 30 patients with benign breast diseases, and 40 healthy women, and peripheral blood mononuclear cells (PBMCs) were isolated. Total RNA was extracted and cDNA was synthesized. PCR was used to amplify 8 breast cancer-related genes: hMAM, HER2, CK19, SBEM, EPG2, hTERT, beta-HGG, and B305D. Suspension array of the PCR products was developed and underwent Luminex 100 laser Flow-type analysis to read the fluorescence signal. COX proportional hazard model was used to find the independent prognostic predictors of breast cancer metastasis. hMAM expression was detected in 57.5%, HER2 in 57.5%, CK19 in 53.4%, SBEM in 52.1%, EPG2 in 31.5%, hTERT in 26.1%, beta-HCG in 21.9%, and B305D in 15.1% of the blood samples respectively. Compared with serum CA15-3 detection, the multigene detection has higher sensitivity (P < 0.05). The expression of SBEM-mRNA in the peripheral blood was correlated with the stage of breast cancer (P < 0.05); and hMAM, SBEM, HER2, and ER could be considered as the independent prognostic predictors of breast cancer metastasis (all P < 0.05). The suspension array assay thus developed is practical in diagnosis of the prognosis of breast cancer. The expression of hMAM, SBEM, and HER2 in peripheral blood can be considered as the independent prognostic predictors of breast cancer metastasis.

Evaluation of mRNA markers for micrometastases detection by RT-PCR in lymph nodes (LN), peripheral blood (PB) and bone marrow (BM) of breast cancer patients (pts)

20068 Background: Previous RT-PCR study showed that hMAM and CEA mRNA could be detected in 95% and 78% breast carcinomas, respectively. Analyzed in normal LN, these two markers were the only ones not expressed, compared to other mRNA markers which could be detected in a variable number of cases (Marchetti 2001). We evaluate the expression of CEA and hMAM mRNA in breast cancer pts in order to investigate if the identification of these transcripts could be correlated to in the LN, PB and BM. Methods: Tumor, normal gland, LN and PB were obtained from 49 breast cancer pts who have been referred to surgery during the period of Jun/2000 to Jan/2004.BM could be obtained from 21 of these cases. Before the manipulation of the tumor, 5 mL of PB was collected and 5 mL of BM was aspirated from the iliac crest. First level axillary LN were sectioned in two. One of the halves was immediately frozen in liquid nitrogen. CEA and hMAM transcripts have been analysed by RT-PCR. Results: Tumors were positive for CEA in 38 (77.6%) cases and LN were positive in 15 cases (36.7%). 6/49 pts expressed CEA in normal breast (12.2%). Five of these, tumor also expressed CEA. Two pts (4.1%) showed CEA expression in PB and in BM. One patient expressed CEA in BM but not in PB. All pts that showed expression in PB, BM and LN, also showed transcript of CEA in tumor. hMAM transcripts were found in 39 (79.6%) normal gland tissue and in 41 of tumor samples (85.7%). LN were positive to hMAM in 12 cases (24.5%). 5 of these (10.2%) were also positive in PB and BM samples. The pts showing hMAM expression in PB, BM and LN also showed its expression in neoplasic tissue. Analyzing both markers, two pts showed the expression of CEA and hMAM in the PB and BM samples. In 21 of the 49 cases the comparison of hMAM and CEA was possible to be performed in all tissues. CEA and hMAM expression associated to larger number of LN affected. Conclusions: CEA and hMAM transcripts can be detected in majority of breast cancer tissue. Specificity of hMAM seems to be higher than CEA, which can be detected in more than 10% of non-tumor breast tissue. Synchronicity of CEA or hMAM expression in the tumor and in extra-mammary sites was high, suggesting that these markers may provide an interesting strategy for follow-up micrometastatic disease. No significant financial relationships to disclose.

Real-time RT–PCR correlates with immunocytochemistry for the detection of disseminated epithelial cells in bone marrow aspirates of patients with breast cancer

Real-time reverse transcriptase–polymerase chain reaction (RT–PCR) is a technique with the potential of improving the quantification of disseminated epithelial cells (DEC) in haematological tissues due to its exquisite sensitivity. This sensitivity may lead to false positivity. Immunocytochemistry (ICC) is regarded as the standard methodology to diagnose DEC. In this study, detection with ICC was compared with quantitative real-time RT–PCR for CK-19 and mammaglobin (hMAM) mRNA in bone marrow (BM) of patients with metastatic breast cancer (MBC). Bone marrow was aspirated from 14 control patients and from 29 patients with MBC. Mononuclear cells (MNC) were isolated. Immunostaining was carried out with the Epimet kit. Quantitative PCR was performed on the ABI Prism 7700. The CK-19 and hMAM mRNA quantities were normalised against β-Actin and calculated relative to a calibrator sample (relative gene expression). All controls were negative by ICC and for hMAM expression measured by RT–PCR, whereas the median RGE value for CK-19 was 0.57. For the MBC patients, the median RGE for hMAM was 0 and 10 out of 25 (40%) tested positive. Median RGE for CK-19 was 2.9 and 20 out of 25 (80%) tested positive. With ICC, the median value was 1 stained cell per sample, and 15 out of 24 (62%) samples were positive. A correlation was observed between CK-19 and hMAM expression (r=0.7; P=0.0003), and between hMAM expression and ICC (r=0.6; P=0.003). CK-19 expression and ICC (r=0.9; P<0.0001) showed the strongest correlation. Reverse transcriptase–polymerase chain reaction for CK-19 resulted in a higher number of positive BM samples of patients with MBC than ICC. Since an excellent correlation is observed between ICC and RT–PCR, and RT–PCR is probably more sensitive with the advantage of being less observer dependent and thus also more easy to automate, we consider our quantitative real-time RT–PCR method as validated for the detection of DEC in the bone marrow of breast cancer patients.

Elevated mammaglobin (h-MAM) expression in breast cancer is associated with clinical and biological features defining a less aggressive tumour phenotype.

Mammaglobin (h-MAM) is expressed mainly by breast epithelial cells, and this feature has been used to detect circulating breast cancer cells and occult metastases in sentinel axillary lymph nodes of breast cancer patients. However, the biological role of mammaglobin is completely unknown. We studied 128 fresh-frozen breast cancer specimens by means of reverse transcriptase-polymerase chain reaction and quantified their h-MAM mRNA expression. This was then correlated with histological and nuclear grade, oestrogen and progesterone receptor expression, c-erb-B2 and mutant p53 expression, as well as with cellular proliferation measured by means of the Ki67 labelling index, DNA ploidy and S-phase, and finally with the presence or not of invaded axillary nodes in the mastectomy specimen. In the univariate analysis, high h-MAM expression (above the median for the whole group) correlated significantly (P < 0.05) with oestrogen and progesterone receptor expression, diploid DNA content, low Ki67 labelling index, low nuclear grade and almost significantly (P = 0.058) with the absence of axillary nodal invasion in the mastectomy specimen. In a final, multivariate model, only progesterone receptor expression, diploid DNA content and absence of nodal invasion were found to be independently associated with high h-MAM expression. All of the features associated with mammaglobin expression reflect, without exception, a less aggressive tumour phenotype. Further studies are needed to clarify whether this is attributable to h-MAM expression itself, or to another mechanism of which mammaglobin expression forms part.

Mammaglobin Expression in Gynecologic Malignancies and Malignant Effusions Detected by Nested Reverse Transcriptase-Polymerase Chain Reaction

The detection of micrometastatic disease remains a challenge for the diagnosis and monitoring of malignant disease. RT-PCR for human mammaglobin (hMAM) was recently shown to provide a sensitive method for assessing circulating breast cancer cells in peripheral blood. This study was aimed at investigating hMAM expression in normal and malignant tissue from the female genital tract and the prostate as well as in malignant effusions derived from gynecologic malignancies. hMAM expression was analyzed with nested RT-PCR in 152 samples of normal (n = 73) and malignant epithelial tissues (n = 79) and in 33 specimens of various normal mesenchymal tissue types. We found hMAM expression was not restricted to the normal mammary gland and breast carcinoma but was also detectable in most specimens of benign and malignant epithelial tissue from the ovary (97% versus 95%), uterus (both 100%), and cervix (91% versus 90%). Notably, hMAM expression was also found in benign prostatic hyperplasia (45%) and in prostate cancer (55%). A much lower expression rate was found in various normal and benign mesenchymal tissues (12%). In keeping with our previous data, hMAM expression was absent in all control samples (n = 124) of peripheral blood and bone marrow from healthy volunteers and patients with hematologic malignancies. In pleural or peritoneal effusions (n = 42) from patients with carcinomas of the breast, endometrium, or ovary, hMAM positivity was noticed in the majority of cases (74%), whereas only 52% of the specimens were cytologically positive for tumor cells. In conclusion, hMAM expression assessed by nested RT-PCR is a sensitive molecular marker for detecting micrometastatic tumor spread into pleural effusions and ascites from patients with breast cancer and various other gynecologic neoplasms.

Detection of mammaglobin expressing cells in blood of breast cancer patients

Expression of human mammaglobin (hMAM) was published to be exclusively expressed in mammary tissue, in solid tumors, axillary lymph nodes and disseminated cancer cells in blood of breast cancer patients. A quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) test was applied to investigate hMAM expression in blood of breast cancer patients. Mammaglobin mRNA expression was found not only in breast cancer cell lines but also in cell lines of other cancer origin. In our patient cohort hMAM expression in 11/98 (11%) samples of breast cancer and 3/12 (25%) ovarian cancer patients could be detected. hMAM mRNA expression as a candidate marker for the detection of disseminated cancer cells in blood of breast cancer patients showed low sensitivity and reduced tissue specificity. A prognostic significance of hMAM expression could not be demonstrated.

Detection of circulating mammary carcinoma cells in the peripheral blood of breast cancer patients via a nested reverse transcriptase polymerase chain reaction assay for mammaglobin mRNA.

According to current medical research, mammaglobin (hMAM) is expressed exclusively in the mammary glands of adult women and in mammary tumor cell lines. Therefore, we examined hMAM expression as a marker for the detection of carcinoma cells in the peripheral blood of patients with breast cancer (BC). Blood samples obtained from 114 BC patients at the various stages of their disease and from 68 individuals without BC were screened for hMAM mRNA by a nested reverse transcriptase polymerase chain reaction (RT-PCR) assay. The assay exhibited a calculated analytical limit of one tumor cell per 10(6) to 10(7) WBCs. None of the samples from peripheral blood of 27 healthy individuals were positive, whereas 29 (25%) of 114 samples from BC patients were positive for hMAM mRNA. hMAM mRNA expression was detected in five (28%) of 18 BC patients at diagnosis, in three (6%) of 53 with no evidence of disease, and in 21 (49%) of 43 with metastatic disease. These results correlate with patients' carcinoembryonic antigen (CEA) plasma level and, to some extent, with estrogen receptor status. Two of 41 samples from patients with malignancies other than BC were also positive. In contrast to healthy volunteers, hMAM transcripts were detected in the peripheral blood of BC patients. The percentage of positivity relates to the clinical stages of disease, CEA plasma level, and estrogen receptor status. Aberrant hMAM expression might occur occasionally in malignancies other than BC. The clinical relevance of hMAM RT-PCR-based tumor cell detection in the peripheral blood of BC patients should be further evaluated in prospective studies.