Programmed death-ligand 1 expression and tumor-infiltrating lymphocytes in colorectal adenocarcinoma

Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) are considered have a prognostic value in several malignancies. This study investigated the correlation between PD-L1 expression of tumor cells with the degree of stromal TILs in colorectal adenocarcinoma.

A cross sectional study design performed by taking 52 colorectal adenocarcinoma samples. The specimens were stained by immunohistochemical procedure using PD-L1 rabbit monoclonal antibody and the degrees of TILs were assessed base on hematoxylin and eosin (H&E) staining.

From a total of 52 samples, the positive PD-L1 expression of tumor cells were 44 (84.6%) samples with 22 (50.0%), 18 (40.9%) and 4 (9.1%) samples had low-, moderate-, and high-degree TILs, respectively. While the negative PD-L1 expression were eight (15.4%) samples with 1 (12.5%), three (37.5%) and four (50.0%) samples had low-, moderate-, and high-degree TILs, respectively. A value of P=0.017 (P<0.05) was obtained by the Chi-square test.

This study concluded that there was a significant correlation between PD-L1 expression of tumor cells and the degree of TILs in colorectal adenocarcinoma. This result indicated that the degree of TILs had the potential to be used as a predictive factor for PD-L1 expression of tumor cells in colorectal adenocarcinoma.