Abstract :
Background: Breast cancer is a heterogeneous disease with different biological and histological properties due to genetics and epigenetic changes with varying clinical features and treatment responses. This study was planned and carried out with the objective to classify breast cancers molecularly using surrogate markers, ER, PgR, Her2/neu and Ki67 and correlate the various types with conventional prognostic markers.
Materials and Methods: 70 cases of invasive breast carcinomas were subjected to routine staining and immunohistochemistry with estrogen receptors(ER), progesterone receptors (PgR), Her2/neu and Ki67and classified into molecular subtypes as defined in various studies. These were correlated with other conventional prognostic parameters and analyzed statistically.
Result: 70 cases of invasive breast cancer were classified into 18(22%) cases of luminal B, 16(25%) cases of Her2/neu and triple negative each and 14(22%) cases of luminal A subtypes. There was an even distribution of molecular subtypes varying from 22 to 28%. Luminal B and Her subtype were commoner in the Indian setting as compare to other studies. Luminal A and Luminal B subtypes were commoner in patients older than 50 years. Her2/neu and TNBC cases were more commonly of higher histological grade and pathological stage, while Luminal A and B subtypes showed lower grade and stages. Luminal B subtype and Her2/neu subtypes showed DCIS more often and Luminal B and TNBC subtypes, more
frequent lymph node metastasis.
Conclusion: The molecular classification of breast cancer by IHC in this study population showed an almost equal distribution of the 4 subtypes. The association of tumor grade and LVI with the molecular subtypes showed a significant correlation.
Keyword :
ER, PR, Her2/neu, Ki67.