Prevalence of Basal-like Breast Cancer among Indigenous Black Zambians at the University Teaching Hospital, Lusaka, Zambia

Abstract

Background: Breast cancer comprises a group of very diverse diseases, which can be demonstrated at the molecular,  histopathological and clinical levels. Gene expression studies using RNA microarray studies have categorised breast carcinomas into several classes. Of these basal-like tumour class has showed poor prognosis and their insensitivity to hormonal therapy  makes therapeutic management difficult . Immunohistochemistry using certain Cytokeratins such as CK 5/6 has made it easier to identify these tumours allowing for better  management. We conducted this study to determine whether the Zambian women  presenting with breast cancer at the University Teaching Hospital express CK5/6 protein.

Materials and methods: This was a cross-sectional study conducted to evaluate 44 conveniently sampled breast tissue  diagnosed with breast cancer on histology at the University Teaching Hospital. The breast tissue was stained with CK 5/6  antibody (Dako, Glostrup, Denmark). The Labelled Streptavidin Binding (LSAB) staining was used to amplify and view the reaction. Pearson-chi-square test was used to indicate statistical significance of the findings.

Results: Results revealed that 23 (52%) of the 44 samples tested negative for CK5/6 while 21(48%) were positive as shown in table 2. Out of the 23 samples that tested positive, 18 were ductal carcinoma while 5 were lobular carcinoma (P = 0.023).

Conclusion: In our study close to half of the tissue specimen were positive for the monoclonal antibody CK 5/6. This is highly suggestive of the presence of Basal like tumours in Zambian patients. These basal-like tumours are highly aggressive and have a greater propensity to metastasize. These tumours are also associated with BRCA ½ genes suggesting a hereditary role in the pathogenesis. There is need therefore to do more studies in breast cancer characterisation in order to develop better strategies in the management of patients with these tumours.