e11043 Background: Breast cancer patients younger than 40 years are known to have an aggressive disease than their older counterparts. In this correlational study involving Indian women with breast cancer; we analyzed if age is related to an aggressive histopathologic phenotype and biomarker expression. Methods: Paraffin embedded tissue blocks of hundred chemotherapy naive breast cancer patients with a diagnosis of invasive breast carcinoma were stratified for age group (less than forty and above forty years) equally from the hospital biorepository. Tissue samples were analyzed for pathological stage, histological type, ER, PR and Her2 Neu receptor status, and expression of biomarkers such as Ki67, EGFR and P53 using immunohistochemistry. Data were analyzed using Chisquare test for proportions. Results: Younger age group had significantly higher grade (p=0.03), higher incidence of solid (p=0.04) and micropapillary type DCIS (p=0.004), ER negativity (p=0.04), higher proliferation rate as indicated by over expression of Ki 67 (p=0.03) and triple negativity (p= 0.03) indicating an aggressive histological phenotype compared to older age group. Conclusions: Results suggest that younger breast cancer patients have an aggressive histological phenotype that may affect treatment response. Future studies should explore relationship of these biomarkers to survival and treatment outcomes.