The Association of Tumor-Infiltrating Lymphocytes and Programmed Cell Death 1 Expression with the Incidence of Distant Metastasis in Triple-Negative Breast Cancer Subjects in Sanglah General Hospital, Bali, Indonesia

The triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with a high rate of distant metastasis. The tumor immunity microenvironment plays an important role, including tumor-infiltrating lymphocytes (TIL) and PD-1 (programmed cell death 1)/PD-L1 (programmed cell death-ligand 1), in promoting TNBC aggressiveness. This study aimed to determine the association of TIL and PD-L1 expression with the incidence of distant metastasis in TNBC. This study is a cross-sectional study involving TNBC subjects at Sanglah General Hospital, Denpasar, conducted in 2019. The parameters analyzed were the expression of TIL, PD-L1, and the incidence of distant metastasis. The expression of TIL was analyzed histopathologically while PD-L1 was measured with Ventana PD-L1 kit test. Subject characteristics were obtained from medical records. Data were collected and analyzed by SPSS 22.0. As many as 31 subjects with TNBC were included in this study, with 51.6% subjects with distant metastasis. The majority of subjects with distant metastasis had low TIL and low tumoral PD-L1 but high PD-L1 stromal in TIL. From statistical analysis, only PD-L1 stromal in TIL expression was associated significantly with distant metastasis (p = 0.043). In conclusion, there was a significant association between PD-L1 stromal in TIL and the incidence of distant metastasis in TNBC.