Frequency of the basal-like phenotype in African breast cancer.

Basal-like breast carcinoma has been recognized as a subtype with specific prognostic implications. However, there is a lack of reports about this category of breast tumors in African women. The aim of this study was to explore the basal-like phenotype in breast cancer patients in an African population, and a registry-based series was included from the well-defined Kyadondo County in Uganda (1.7 millions). We studied a total of 65 archival paraffin blocks of invasive breast cancer using antibodies against cytokeratin 5/6 and P-cadherin, and these markers were expressed in 34% of all cases and in 52% of ER (estrogen receptor)-negative tumors. All basal-like tumors were ER negative (p<0.0005) and PR (progesterone receptor) negative (p=0.002). Basal-like breast carcinomas were of a higher histologic grade (p=0.001), had high mitotic counts (p=0.002), and marked nuclear pleomorphism (p=0.002). P-cadherin-positive tumors had a high Ki-67 proliferative rate (p=0.039). In conclusion, the basal-like phenotype is frequent in this African series of breast cancer and is strongly associated with poor prognostic factors. Our findings might be significant in relation to clinical management of these patients, including novel targeted therapy.