Breast carcinoma histopathological correlation with molecular classification: A comparative study

Abstract

Breast cancer is the most common malignancy in females. It isroutinely classified according to the WHO classification. However, molecular classification can be more powerful than histopathology as a predictive factor for the different treatment strategies. This study gives an insight to overall prognosis, role of molecular markers, various molecular subtypes and better categorization of triple negative breast cancer cases.This was a cross sectional study conducted in the department of pathology over a period of 2 years.In this study, 500 cases of breast carcinoma were included. Molecular phenotype was determined using expression of estrogen receptor, progesterone receptor, HER2/neu, Ki67, epithelial growth factor receptor (EGFR), and cytokeratin 5/6. Correlation of molecular subtypes with histological grade, prognostic and predictive factors done by using chi square test. Using software Medcalc version 12.2.1.0.Of the 500 cases, maximum number of cases 38.20% were luminal A. Most common histological subtype in all category were Infiltrating duct carcinoma (Not Otherwise Specified) {IDC (NOS)} with higher grade of IDC (NOS) in her2neu and basal type. Unclassified category includes both low grade tumors and high grade tumors. Statistically significant association of molecular subtype was found with histological subtype, tumor necrosis, lymphocytic response and lymphovascular invasion. (P ≤ 0.001) Molecular classification would result in less frequent use of chemotherapy in breast carcinoma and have its considerable advantages in reducing toxicity and costs.In view of increasing awareness, younger age of presentation and occasional family history various screening program should be popularized.