Immunohistochemical and molecular subtypes of breast cancer in Nigeria

Previous studies suggest that the majority of breast cancer in Africans are hormone receptor negative and thus differ from breast cancer in other populations. We decided to evaluate the hormone receptor status of patients seen in our practice to see if they indeed differ from that of other populations.

We prospectively collected and analyzed tumors from consecutive patients presenting to our clinic over an 18 months period from July 2004. During the period, we saw 192 patients without previous histological diagnosis and conducted routine histological and immunohistochemical analysis of their tumors for hormone receptor status.

Most, 65.1% of tumors were ER+, 54.7% were PR+ and 79.7% were HER2 negative. Majority of the tumors, 77.6% were luminal type A, 2.6% were luminal type B, 15.8% were basal type and the remaining 4.0% (6/152) were HER2+/ER- subtype. We found an association between hormone receptor status and tumor grade but not with stage at presentation.

We conclude that there is no difference in the pattern of hormone receptors in breast cancer patients of African origin compared to other populations and urge more use of hormone manipulation for management of breast cancer in this population.