Expression of Programmed Death Ligand1 (PD-L1) in Gastric Carcinoma (Histopathological and Immunohistochemical Study)

To evaluate immunohistochemical expression of PD-L1 in cases of gastric adenocarcinoma. To correlate PD-L1 immuno-histochemical expression with other available clinico-pathological parameters such as age, sex, grade, stage, lymph node (L.N) metastasis and others.

The present retrospective study retrieved the data and archived paraffin blocks of 60 cases of Gastric carcinoma. Immunohistochemical evaluation was done to assess the expressions of PD-L1 in the tumor cells (TC), tumor infiltrated lymphocytes (TILs) and combined positive score (CPS).

TC PD-L1 expression was detected in 56.7% of cases, TILs PD-L1 expression was detected in 53.3 % of cases and CPS PD-L1 expression was detected in 63.3% of case, with no statistically significant correlation with clinico-pathological parameters except TILs PD-L1 expression showed statistically significant correlation with positive TILs (P value ˂0.019).

Our findings supported the expression of PD-L1 by TC, TILs, and CPS in gastric cancer, with increased expression in a subpopulation of TILs rich in PD-L1 identifying them as potential targets for PD-1/PD-L1 therapy.