Molecular Subtyping, Receptor Concordance, and Magee Score Assessment in Breast Carcinoma: An Immunohistochemical Study.

BACKGROUND: Breast carcinoma is a heterogeneous disease characterized by variable expression of estrogen receptor (ER), progesterone receptor (PR), HER2/neu, and Ki-67, which influence molecular classification and therapeutic decision-making. This study evaluated the immunohistochemical profile of invasive breast carcinoma, assessed receptor concordance between primary tumors and corresponding metastatic deposits, and estimated recurrence risk using Magee score equations. METHODOLOGY: This cross-sectional study was conducted on 30 cases of invasive breast carcinoma. Immunohistochemical expression of ER, PR, HER2/neu, and Ki-67 was evaluated, and molecular subtypes were classified accordingly. Receptor concordance between primary tumors and corresponding metastatic deposits was assessed using McNemar's test for paired categorical data. Magee recurrence scores were calculated to estimate recurrence risk. Descriptive statistics were used to summarize clinicopathological characteristics, and a p-value <0.05 was considered statistically significant. RESULTS: Thirty patients with invasive breast carcinoma were included, with a mean age of 44.8 ± 2.3 years. ER positivity was observed in 23 cases (76.7%), PR positivity in 15 cases (50.0%), and HER2/neu positivity in three cases (10.0%). Luminal A was the predominant molecular subtype, accounting for 22 (73.3%) cases. Among the 19 paired primary and metastatic samples, ER and PR discordance was identified in 14 (73.7%) and 10 (52.6%) cases, respectively, whereas no HER2/neu discordance was observed. Among cases with nodal metastasis, involvement of 1-3 lymph nodes was most frequent, occurring in 11 (57.9%) cases. One patient (5.3%) had distant brain metastasis. H-score analysis demonstrated that ER H-scores of 101-200 and 201-300 were observed in 12 (52.2%) and 10 (43.5%) cases, respectively, whereas PR H-scores of 101-200 and 201-300 were observed in six (40.0%) and eight (53.3%) cases, respectively. Based on aggregate Magee scores, 16 (53.3%) patients were categorized as low risk, nine (30.0%) as intermediate risk, and five (16.7%) as high risk. CONCLUSION: Immunohistochemical profiling revealed a predominance of luminal A tumors and substantial discordance in ER and PR expression between primary tumors and metastatic deposits. Magee score assessment demonstrated that most patients belonged to the low-risk category, supporting its potential utility as a cost-effective prognostic tool in resource-limited settings.