Molecular Classification of Breast Carcinoma Based on the Prognostic Marker: A Clinico-pathological Correlation

Abstract

Background: Breast cancer (BC) has now surpassed lung cancer as the leading cause of global cancer incidence in 2020, with an estimated 2.3 million new cases, representing 11.7% of all cancer cases. It is a highly heterogeneous disease with a variety of morphologic and clinical manifestations which results in a range of responses to treatment. Recently, targeted therapies based on the genetic, hormonal, or immunohistochemical (IHC) subtypes of breast cancer have been used. Objective: The study was a prospective hospital-based observational study with a sample size of 150 cases. The study aimed to determine the distribution of various molecular subtypes of breast carcinoma and also correlate the expression status of ER, PR, Her2neu, and Ki 67 with the patient's age, tumor size, tumor type, histological grade, lymph node status, and TNM staging. Results: 96.7% of cases were invasive ductal carcinoma (NOS). Most of the grade 1 tumors (68.8%) were both ER and PR positive. Grade 2 tumors had almost equal distribution with 39.4% of patients being ER & PR positive and 43.7% being both ER & PR negative. Almost all grade 3 tumors (88.9%) were both ER and PR -negative. Conclusion: IHC markers are cost-effective and easily available worldwide even in resource-poor countries like India. A greater understanding of the molecular classification of breast carcinoma based on triple markers will help in the development of targeted therapies that will lead to increased efficacy, decreased toxicity, increased disease-free survival, and better selection of patients who will benefit from treatment.