Clinicopathologic correlates of molecular subtypes in invasive breast carcinoma: A retrospective cohort study of 500 cases

Dugyala TR, Madigubba S

Pdf Page Numbers :- 17-22

Tejasree Rao Dugyala^1,* and Shailaja Madigubba¹

¹Department of Pathology, Krishna Institute of Medical Sciences, Minister Road, Secunderabad-500003, Telangana, India

*Corresponding author: Dr. Shailaja Madigubba, Department of Pathology, Krishna Institute of Medical Sciences, Minister Road, Secunderabad-500003, Telangana, India. Email: drsailajamadigubba@gmail.com

Received 10 September 2025; Revised 27 October 2025; Accepted 7 November 2025; Published 20 November 2025

Citation: Dugyala TR, Madigubba S. Clinicopathologic correlates of molecular subtypes in invasive breast carcinoma: A retrospective cohort study of 500 cases. J Med Sci Res. 2026; 14(1):17-22. DOI: http://dx.doi.org/10.17727/JMSR.2026/14-3

Copyright: © 2026 Dugyala TR et al. Published by KIMS Foundation and Research Center. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Abstract

Introduction: Breast cancer is a heterogeneous disease, and its molecular subtypes play a key role in predicting relapse risk and guiding treatment decisions, including endocrine therapy, anti-HER2 targeted therapy, and chemotherapy. The Ki-67 proliferation index is widely used to classify molecular subtypes, assess tumor aggressiveness, and predict clinical outcomes. This study aimed to evaluate the distribution of age and tumor grade across molecular subtypes, examine their associations, and analyze variations in Ki-67 levels.

Methods: A retrospective cohort study was conducted on 500 cases of invasive breast carcinoma diagnosed between Feburary 2023 and August 2025 at Krishna Institute of Medical Sciences, Secunderabad, a tertiary care center in South India. Data on estrogen receptor (ER), progesterone receptor (PR), HER2 status, and Ki-67 index were collected from electronic medical records to classify molecular subtypes. Patient age and histologic grade were also analyzed.

Results: Luminal B was the most common subtype (42.2%), including 32.2% HER2-negative and 10% HER2-positive cases, followed by Luminal A (27.2%), triple-negative breast cancer (16.8%), and HER2-enriched (13.8%). High Ki-67 levels were observed in 70.4% of tumors, particularly in Luminal B, triple-negative, and HER2-enriched subtypes. The mean age was 56.45 ± 12.21 years, with most patients (67.2%) aged over 50. Grade 2 tumors were most frequent (53.6%), followed by grade 3 (29.8%) and grade 1 (16.6%), with significant associations between subtype, age, and grade.

Conclusion: Luminal B predominated, and higher Ki-67 expression correlated with more aggressive subtypes. Molecular classification and Ki-67 assessment are essential for treatment planning and prognosis, emphasizing the importance of early detection and awareness.

Keywords: breast cancer; molecular subtypes; tumor grade; luminal A; luminal B; HER 2 enriched; triple negative