Pattern of hormone receptors and human epidermal growth factor receptor 2 status in sub-Saharan breast cancer cases: Private practice experience.

INTRODUCTION: Breast cancer is the most common cancer among women globally. With immunohistochemistry (IHC), breast cancer is classified into four groups based on IHC profile of estrogen receptor (ER)/progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2/neu) expression, positive (+) and/or negative (-). The IHC classification correlates well with intrinsic gene expression microarray categorization. ER-positive tumors may benefit from being treated with selective ER modulators and aromatase inhibitors, whereas patients with HER2/neu positive tumors have been shown to experience a significant survival advantage when treated with humanized monoclonal antibodies against HER2/neu.

OBJECTIVE: To determine ER/PR, HER2/neu expression and their association with histological prognostic markers in female breast carcinomas seen in a private diagnostic laboratory based in Lagos.

MATERIALS AND METHODS: Immunohistochemistry reports of breast cancer patients, which were diagnosed by histopathology section of a private diagnostic laboratory based in Lagos, Nigeria from August 2009 to August 2014.

RESULTS: About 18.7% of breast cancers had IHC (ER, PR and HER2) done on them and were all females. The mean age of all subjects was 49.5 years (standard deviation, 13.2; range, 29-78 years). Most (95.8%) of the breast cancers were of invasive ductal carcinoma type, with 77.4% of them been >5 cm. IHC pattern was as follows: ER/PR+, HER2-=19 (39.6%), ER/PR-, HER2- (triple negative [TN])=14 (29.2%), ER/PR+, HER2+=9 (18.8%), ER/PR-, HER2+=6 (12.5%), corresponding to Lumina A, TN/basal-like, Lumina B and HER2 over expressed respectively.

CONCLUSION: Triple negative breast cancers are common in our environment and affect young females most and could be contributory to the poorer prognosis of breast cancer in our environment.