Her-2/NEU receptor expression in breast cancer and its correlation with the other established prognostic parameters at Kenyatta National Hospital

Abstract

Breast cancer is quickly becoming a burden to the Kenyan healthcare system as the disease prevalence has been on an upward trend. It is the second commonest malignancy affecting Kenyan females. Some patients with breast cancer show over expression of HER-2 oncoprotein and this affects the biological behaviour of the malignant cells and the tumour response to therapeutic agents. The pattern of this receptor expression and its utility have not been adequately explored in Kenyan breast cancer patients. The objective of this study was to determine the prevalence ofHER-2 receptor expression in breast cancers seen at KNH and correlate the results with the other parameters for poor prognosis.

This was a descriptive cross-sectional study of breast cancer patients at KNH. A sample size of 133 ( 50 from the breast clinic/wards and 83 from information in the records department) cases of breast cancer diagnosed through histology had their malignant cells analyzed for HER-2 expression by immunohistochemical methods. Immunohistochemical findings were correlated with age, histological type, tumour grade, tumour size, axillary lymph node status and clinical stage.

HER-2 was over expressed in 33.8% of the cases. The mean age of breast cancer cases with HER-2 overexpression was 50.3 years while that of cases without over expression was 48.9 years ( p =0.578 ). No significant correlation between HER-2 over expression and histological type was established. HER-2 positive tumours tended to be larger than HER-2 negative tumours but this was not statistically significant. The proportion of tumours with HER-2 over expression within each grade increased linearly with the grade but still no significant correlation was noted. No association was seen between clinical stage and HER-2 status but a strong correlation between HER-2 over expression and axillary lymph node status was established ( p = 0.013 ).

HER-2 over expression was seen in 33.8% of breast cancer patients at KNH. HER-2 was significantly correlated with axillary lymph node status but there was no association between HER-2 positivity and age, histological type, tumour size, histological grade, and clinical stage.