MOLECULAR CLASSIFICATION OF BREAST CANCERS SEEN IN LAGOS UNIVERSITY TEACHING HOSPITAL: A RETROSPECTIVE STUDY

Abstract

Background: Breast cancer is the most common malignancy worldwide, occurring in both men and women, although male breast cancer is rare.1 Breast cancers can be classified according to molecular methods (in this study, immunohistochemistry) into Luminal A, Luminal B, HER 2 over expressing and Basal-like breast cancers. Breast cancers can also be classified into hereditary and non-hereditary (sporadic breast cancers). Hereditary breast cancer accounts for 3 – 5% of all breast cancers.8 BRCA 1 and BRCA 2 gene mutation were identified as contributing factors to genetic predisposition in hereditary breast cancers.8 In the general population, about 5 – 10% of all breast cancers can be attributed to the presence of BRCA 1 and BRCA 2 gene mutations. Aim/Objective: To determine the molecular classification of breast cancer in Lagos University Teaching Hospital (LUTH). Materials and Methods: This study was conducted in the Department of Anatomic and Molecular Pathology, Lagos University Teaching Hospital (LUTH), Lagos in South Western Nigeria. Using systematic sampling 83 female breast cancers diagnosed in LUTH between 2011 – 2013 were analysed. The molecular class of these breast cancers were determined using immunohistochemistry. The histopathological classification, histological grade and E-cadherin expression of these breast cancers were also determined. Results: The most predominant histopathological diagnosis of the breast cancers studied was invasive carcinoma of no special type (NST). The majority of these breast cancers were high grade tumours. The most predominant molecular class was triple negative breast cancers of which basal-like breast cancers form the majority.

Conclusion: This study further emphasizes the need for ancillary tests in breast cancer tissues after routine H & E (Haematoxylin & Eosin) diagnosis. These include using immunohistochemistry to determine their molecular class. Ecadherin is necessary to confirm or rule out the presence of a lobular carcinoma. These ancillary tests help in prognostication and management (treatment).

MOLECULAR CLASSIFICATION OF BREAST CANCERS SEEN IN LAGOS UNIVERSITY TEACHING HOSPITAL: A RETROSPECTIVE STUDY