Male breast cancer according to tumor subtype and race: a population-based study

BACKGROUND

Breast cancer occurs rarely in men. To the authors' knowledge, no population-based estimates of the incidence of human epidermal growth factor receptor 2 (HER2)-positive breast cancer or of the distribution of breast cancer subtypes among male breast cancer patients have been published to date. Therefore, the objective of the current study was to explore breast tumor subtype distribution by race/ethnicity among men in the large, ethnically diverse population of California.

METHODS

This study included men who were diagnosed with invasive breast cancer between 2005 and 2009 with known estrogen receptor (ER) and progesterone receptor (PR) (together, hormone receptor [HR]) status and HER2 status reported to the California Cancer Registry. Among the men with HR-positive tumors, survival probabilities between groups were compared using log-rank tests.

RESULTS

Six hundred six patients were included. The median age at diagnosis was 68 years. Four hundred ninety-four men (81.5%) had HR-positive tumors (defined as ER-positive and/or PR-positive and HER2-negative). Ninety men (14.9%) had HER2-positive tumors, and 22 (3.6%) had triple receptor-negative (TN) tumors. Among the patients with HR-positive tumors, non-Hispanic black men and Hispanic men were more likely to have PR-negative tumors than non-Hispanic white men. No statistically significant differences in survival were observed according to tumor subtype (P = .08). Differences in survival according to race/ethnicity were observed among all patients (P = .087) and among those with HR-positive tumors (P = .0170), and non-Hispanic black men had poorer outcomes.

CONCLUSIONS

In this large, representative cohort of men with breast cancer, the distribution of tumor subtypes was different from that reported for women and varied by patient race/ethnicity. Non-Hispanic black men were more likely to have TN tumors and ER-positive/PR-negative tumors than white men.

Prognostic indicators in male breast carcinoma

Twenty-nine male breast cancers (MBC) were studied to determine the relationship between expression of several prognostic factors and clinical outcome. Immunohistochemistry employing a labeled streptavidin-biotin method was used to detect the presence of estrogen (ER) and progesterone receptors (PR), cathepsin D (CD), c-erbB-2 oncoprotein, epidermal growth factor receptor (EGFR), and p53; results were visually semiquantitated. DNA ploidy was evaluated by image analysis (CAS 200) of 5 μm fixed embedded Feulgenstained tissue sections. For proliferating cell nuclear antigen (PCNA), nuclear immunostain was quantitated as percentage positive nuclear area (PPNA) by image cytometry (CAS 200). The frequency of expression was ER, 26/29 (89.7%); PR, 19/29 (65.5%); CD, 25/29 (86.2%); c-erbB-2, 5/29 (17.2%); EGFR, 4/29 (13.8%); and p53, 9/29 (31%). Twenty-one (72.4%) were aneuploid; the mean PPNA for PCNA was 37.87% (control 13%). Of 20 patients, 10 (50%) MBC had lymph node metastases; 6 (21%) had distant metastases to lung (1) and bone (5). Five of the patients died of MBC. Excluding the patients with only ductal carcinoma in situ, the 1-and 5-year survival rates were 90.5% and 56.3%, respectively. In this comprehensive study of a large number of available prognostic markers, their frequency (with the exception of higher ER and CD) and prognostic significance were similar to that in female breast carcinoma. Among clinical and standard pathologic unfavorable prognostic indicators, age ≥ 62 years was significant (p = .004). Trends toward reduced survival were associated with axillary lymph node metastases (p = .145), ER negativity (p = .058), PR negativity (p = .116), and aneuploid DNA content (p = .201).

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.

Targeted therapy in breast cancer: the HER-2/neu gene and protein

The HER-2/neu oncogene, a member of the epidermal growth factor receptor or erb gene family, encodes a transmembrane tyrosine kinase receptor that has been linked to prognosis and response to therapy with the anti-HER-2-humanized monoclonal antibody, trastuzumab (Herceptin, Genentech, South San Francisco, CA) in patients with advanced metastatic breast cancer. HER-2/neu status has also been tested for its ability to predict the response of breast cancer to other therapies including hormonal therapies, topoisomerase inhibitors, and anthracyclines. This review includes an analysis of 80 published studies encompassing more than 25,000 patients designed to consider the relative advantages and disadvantages of the various methods of measuring HER-2/neu in clinical breast cancer specimens. Southern blotting, PCR amplification detection, and fluorescence in situ hybridization assays designed to detect HER-2/neu gene amplification are compared with HER-2/neu protein overexpression assays performed by immunohistochemical techniques applied to frozen and paraffin-embedded tissues and enzyme immunoassays performed on tumor cytosols. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The role of HER-2/neu testing for the prediction of response to trastuzumab therapy in breast cancer is reviewed along with the current studies designed to test whether HER-2/neu status can predict the response to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review will also evaluate the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.

The Her-2/neu gene and protein in breast cancer 2003: biomarker and target of therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. In this review, the association of HER-2/neu gene and protein abnormalities with prognosis and response to therapy with trastuzumab and to other therapies in breast cancer is presented. By considering a series of 80 published studies encompassing more than 25,000 patients, the relative advantages and disadvantages of Southern blotting, polymerase chain reaction amplification, and fluorescence in situ hybridization assays designed to detect HER-2/neu gene amplification are compared with HER-2/neu protein overexpression assays performed by immunohistochemical techniques applied to frozen and paraffin-embedded tissues and enzyme immunoassays performed on tumor cytosols. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The role of HER-2/neu testing for the prediction of response to trastuzumab therapy in breast cancer is presented as well as its potential impact on responses to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review also evaluates the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.

Clinical management of breast cancer in males: a report of four cases

Breast cancer in men is a rare cancer manifestation, accounting for less then 1% of all breast cancers in both genders. The incidence in Germany during the last years has been approximately 1.0 per year/100,000. In the US, only 0.2% of all malignancies in men. Predisposing risk factors seem to include radiation exposure, hereditary factors, estrogen administration, and diseases associated with hyperestrogenism, such as cirrhosis of the liver or genetic syndromes (i.e. Klinefelter disease). The incidence of male breast cancer is increased in families with a number of first degree relatives affected with breast or prostate cancer. An increased risk of male breast cancer has been reported in families with a mutation of the breast cancer susceptibility gene BRCA-2. For a period of decades, prognosis of breast cancer in males was thought to be worse than that of female patients. Data and cases being published demonstrate that prognosis and strategies of treatment in male breast cancer do not differ from those in females. The cases presented clearly demonstrate that diagnostic work-up, staging procedures and treatment options for primary treatment and advanced stages are identical compared to the recommendation for female breast cancer.

The HER-2/neu oncogene: prognostic factor, predictive factor and target for therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. The potential value of HER-2/neu status for the prediction of disease outcome and response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic and radiation therapies. This review includes the application of serum-based HER-2/neu testing and the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment.

The HER-2/neu oncogene in breast cancer: prognostic factor, predictive factor, and target for therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. In this review, the association of HER-2/neu gene and protein abnormalities studied by Southern and slot blotting, immunohistochemistry, enzyme immunoassays, and fluorescence in situ hybridization with prognosis in breast cancer is studied in depth by review of a series of 47 published studies encompassing more than 15,000 patients. The relative advantages of gene amplification assays and frozen/fresh tissue immunohistochemistry over paraffin section immunohistochemistry are discussed. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The potential value of HER-2/neu status for the prediction of response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic, and radiation therapies. The evidence that HER-2/neu gene and protein abnormalities in breast cancer predict resistance to tamoxifen therapy and relative sensitivity to chemotherapy regimens including adriamycin is presented. The review will also evaluate the status of serum-based testing for circulating the HER-2/neu receptor protein and its ability to predict disease outcome and therapy response. In the final section, the review will briefly present preliminary data concerning the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment. The recently presented phase III clinical trial evidence that systemic administration of anti-HER2 antibodies (Herceptin), alone and in combination with cytotoxic chemotherapy in patients with HER-2/neu overexpressing primary tumors, can increase the time to recurrence and overall response rates in metastatic breast cancer is reviewed.