W187 - Prognostic Value of Computerized Tumor-infiltrating Lymphocytes Analysis in Breast Cancer

Abstract Text: Breast cancer remains one of the leading causes of cancer-related deaths globally, with tumor-infiltrating lymphocytes (TILs) playing a critical role in modulating tumor progression. In this study, we focused on the prognostic value of the eTILs% (the percentage of TILs in relation to the tumor cells) in a cohort of 94 breast cancer patients from Sonora, located in the northern region of Mexico. Patients were classified into three molecular subtypes: luminal (n = 61), HER2+ (n = 20), and triple-negative (TN, n = 13). The study found that eTILs% showed a statistically significant correlation with disease-free survival (DFS) in luminal (cutoff = 3.97%, p = 0.048) and HER2+ (cutoff = 13.45%, p = 0.023) subtypes. Specifically, lower eTILs% levels were associated with a higher risk of recurrence and death in these subtypes. However, in the TN subtype, due to the small sample size, no statistically significant cutoff value was identified, highlighting the need for further investigation with a larger cohort. Additionally, the analysis revealed higher lymphocytic infiltration in HER2+ and TN subtypes compared to luminal tumors (p = 0.04 and p = 0.03, respectively). These findings suggest that eTILs% could be a potential prognostic biomarker, particularly for luminal and HER2+ breast cancers, and that larger studies are necessary to validate its role in TN breast cancer. This study represents one of the first evaluations of eTILs% as a prognostic marker in a Sonoran population and provides valuable insight into the potential utility of immune response-based biomarkers in personalized cancer therapy.