Morphological evaluation of tumor-infiltrating lymphocytes (TIL) is gaining importance as evidence strengthens its clinical relevance as immunological biomarker, in breast cancers. The significance of TIL also lies in the fact that its presence determines the immune response and thereby predicts improved disease outcome independent of chemotherapeutic regimen. The present study was conducted to establish the association of Tumour infiltrating lymphocytes (TIL) with other independent clinicopathological prognostic factors of breast cancer and find their statistical significance. A retrospective study was conducted with random 149 modified radical mastectomy specimens. Data was collected with respect to the following inclusion criteria: age, histological type, histological, grade, tumour size of primary breast cancers, lymph node status, lymphovascular invasion ER, PR, Her 2 neu status by immunohistochemistry. Univariate regression analysis was done for all the variables with TIL. Based on p-value and correlation coefficient these four variables: lymphovascular invasion, histological grade, Her 2 and Triple negative breast cancer (TNBC) showed high association with TIL. Multivariate logistic regression analysis emphasized that the four variables: histological grade, lymphovascular invasion, Her 2 and TNBC together are strongly associated with TIL. Hence the evaluation of TIL density in routine histopathological practice may prove to be of paramount relevance

Keywords: Tumour infiltrating lymphocytes (TIL); Breast cancer; Her 2; Triple negative breast cancer.