ER, PR, Her2, and Ki-67 Expression in Male and Female Breast Cancer
Megan G Lockyer, Elvia Martinez-Blanco, Gordana Verstovsek, Isabelle Bedrosian, Constance Albarracin, Daniel Rosen. Baylor College of Medicine, Houston, TX; MD Anderson Cancer Center, Houston, TX
Background: Male breast cancer afflicts a small percentage of the population and is usually advanced when treatment is sought due to late presentation. Treatment is based on the readily available research done on female breast cancer with few examining the immunophenotypic and clinicopathologic characteristics of male breast cancer. We evaluated the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 (HER2), and Ki-67 among male breast cancer specimens from patients, and compared the results against results from a group of female breast cancer specimens that were previously evaluated.
Design: Samples from men with primary breast cancer between 1995 and 2011 from the Veterans Affairs Hospital and female primary sporadic breast cancer cases from MD Anderson Cancer Center were selected through retrospective review of medical records. Paraffin blocks and complete demographic and clinical follow-up was available in 14 male patients and 39 female patients. Histopathologic diagnoses were based on the ESBR grading system. A tissue microarray block was constructed and stained for ER, PR, Her2-neu, and Ki-67 immunohistochemical stains.
Results: The average age at presentation was 67 in female and 66 in male. A total of 64% of male patients (9 cases) presented at stage 1, 21% (3 cases) at stage 2, and 14% (2 cases) at stage 3. No male patients presented at stage 4 disease or died of disease. A total of 6 female patients (15%) presented at stage 4 disease. Ductal carcinoma was the predominant histologic pattern in both female (85%) and male (93%). Tumor grade was similarly distributed among female and male breast cancers. The average tumor size was 18 mm for female and 26 mm for male cancers. Female breast cancer had a higher proportion of positive nodes and lymphovascular invasion compared to male. All male cases were ER positive, the majority were PR positive (64%) and all were Her2 negative. ER, PR, and Her2 were positive in 74%, 46%, and 26% (2+/3+), respectively, in female cases. The Ki-67 proliferation index was high in 7% of male cases and 31% of female cases.
Conclusions: In our cohort, male tumors presented at an earlier stage, have less positive nodes, and have a similar tumor grade compared to female breast cancer. Male tumors tend to express ER and PR, have a low Ki-67 proliferation index, and are Her2 negative.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 28, Wednesday Afternoon