Original article / research
Year : 2026 Month : April Volume : 15 Issue : 2 Page : BO05 - BO08 Full Version

Immunohistochemical Pattern of Breast Cancer Patients from a Limited Geographical Region of Tamil Nadu, India: A Retrospective Study
Rajiv Kumar Krishnan, R Vishnusri
1. Senior Assistant Professor, Department of Radiation Oncology, Government Villupuram Medical College and Hospital, Villupuram, Tamil Nadu, India. 2. Assistant Professor, Department of Pathology, Government Medical College, Kallakurichi, Tamil Nadu, India.
 
Correspondence Address :
Dr. Rajiv Kumar Krishnan,
Senior Assistant Professor, Department of Radiation Oncology, Government
Villupuram Medical College and Hospital, Mundiampakkam-605601, Villupuram,
Tamil Nadu, India.
E-mail: ungalrajiv@gmail.com
 
ABSTRACT
: Introduction: Breast Cancer is the leading cause of cancer incidence worldwide among females, accounting for 11.6% of all cancers, with an estimated mortality rate of 6.9%, ranking fourth according to Global Cancer Observatory (GLOBOCAN) 2022 statistics. Over the years, BC treatment evolved from being based solely on clinical findings to pathological findings and is now primarily guided by the molecular characteristics of individual tumour types. Current American Joint Committee on Cancer (AJCC) staging and National Comprehensive Cancer Network (NCCN) recommendations are largely based on molecular features of the disease.

Aim: To analyse the pattern of molecular immunohistochemical expression in a limited geographical area of the study centre, with specific reference to luminal subtypes of BC.

Materials and Methods: This retrospective study was conducted at the Department of Radiation Oncology, Government Villupuram Medical College and Hospital (GVMCH), Villupuram, Tamil Nadu, India. Immunohistochemistry (IHC) data from 343 BC patients were analysed. Data were collected from female patients with histologically confirmed BC who had available IHC results between 2014 and 2024. Oestrogen Receptor (ER), Progesterone Receptor (PR), HER2/neu expression, and the proliferation index (Ki-67) were recorded. Cases were grouped according to luminal subtype classification. Associations between individual receptor expression, luminal subtypes, and proliferation index were evaluated. Descriptive statistics were used to summarise demographic and biomarker characteristics. Associations between categorical variables were assessed using the chi-square test. A p-value<0.05 was considered statistically significant.

Results: Of the 343 patients analysed, 137 (39.9%) were classified as Luminal A, 54 (15.7%) as Luminal B, 52 (15.2%) as Human Epidermal Growth Factor Receptor 2 (HER2/neu)-enriched, and 100 (29.2%) as basal-like subtype. Among the 191 patients with available Ki-67 data, 141 (73.8%) demonstrated a proliferation index greater than 20%.

Conclusion:The present study demonstrated that Luminal A was the most prevalent subtype, followed by the basal-like, Luminal B, and HER2/neu-enriched subtypes in this geographical population. This distribution differs slightly from patterns reported in other published studies.
Keywords : Breast neoplasm, Biomarkers, Oestrogen receptor, Progesterone receptor
DOI and Others : DOI: 10.7860/NJLM/2026/81473.2963 Date of Submission: Nov 29, 2025 Date of Peer Review: Jan 02, 2026 Date of Acceptance: Jan 28, 2026 Date of Publishing: Apr 01, 2026 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was Ethics Committee Approval obtained for this study? Yes • Was informed consent obtained from the subjects involved in the study? Yes • For any images presented appropriate consent has been obtained from the subjects. NA PLAGIARISM CHECKING METHODS: • Plagiarism X-checker: Nov 30, 2025 • Manual Googling: Jan 20, 2026 • iThenticate Software: Jan 27, 2026 (1%) ETYMOLOGY: Author Origin EMENDATIONS: 6
 
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