Immunohistochemical Characterization of Breast Cancer at the University Teaching Hospital, Lusaka, Zambia

Abstract

Introduction:Breast cancer remains among the most commonly diagnosed cancers in women. Worldwide, breast cancer comprises 22.9% of all cancers. In Zambia, it is ranked number 2 at 11% after cervical cancer (60%). However, the current prevalence can be reduced through sensitization programmes encouraging women to go for screening for example using mammogram. In this study, the aim was to characterize the histological phenotypes of breast cancer at the University Teaching Hospital in Lusaka, Zambia.Methods:This was a laboratory based cross-sectional study done at the University Teaching Hospital (UTH) in Histopathology laboratory in Lusaka, Zambia for six months. A convenient sampling method was used to select the 44 formalin fixed-paraffin embedded tissue blocks of breast tissue diagnosed with breast cancer on histology for the year 2012. The specimens were from patients aged between 21 and 70 years old. Tissue sectioning, H & E staining, cover slipping and microscopic examinations was done under the supervision of a qualified histopathologist in order to determine the histological types of breast cancer which were later analyzed for the following immunohistochemical profiles-P53, HER2, VEGF and CK5/6. Results:Findings were analyzed using statistical software SPSS for Windows, Version 20. Age, histology and IHC results were variables under consideration. Chi-square and Fisher’s Exact test with a P-Value of less than 0.05 were used to indicate statistical significance of findings.Results revealed that breast cancer was more prevalent 54.5% in the samples from patients that were aged 30-49 years than in those that were 50 years and above 45.5%. On histological evaluation, it was found that most samples 25 (57%) had lobular carcinoma (LC) while 19 (43%) had ductal carcinoma (DC). Further analysis showed that out of the 24 samples that came out positive for breast cancer for those 30-49 years, 13 (52.2%) had LC while 11 (45.8%) had DC. Similarly, samples from those that were aged 50 and above showed a similar pattern with LC accounting for the majority: 12 (60%) out of the total of 20 samples with only 8 (40%) DC. On IHC analysis, P53 and VEGF were overexpressed in LC than DC while CK5/6 was over expressed in DC than LC. HER2 was equally expressed in LC and DC.Discussion:The study has shown that breast cancer is more frequent between the ages of 30-49 years and that breast cancer in Zambia is predominantly of LC and DC histological types although lobular carcinoma is found to be with higher frequency than DC. Further IHC analysis revealed that P53 and VEGF were overexpressed in LC than DC while CK5/6 was over expressed in DC. However, HER2 was equally expressed in both LC and DC.