Evaluation of the Relationship of PD-L1 and FOXP3 Expressions With Clinicopathological Parameters in Gastric Carcinomas

Abstract

Objective: At the time of diagnosis, gastric cancers are generally at an advanced stage and the survival rates are very low. The aim of this study is to determine the prognostic values of PD-L1 expression in gastric carcinomas and to detect the presence of FOXP3- positive Treg cells in tumor microenviroment. Method: In this study, PD-L1 and FOXP3 expressions were evaluated in 125 patients with gastric carcinoma who had undergone gastrectomy between 2011, and 2015. Results: The mean age of the patients was 64.18+-12.3 years and the patients were followed up for a mean period of 29.6+-26.4 months. In only 2 (1.6%) cases there were weak membranous expressions of PD-L1 in tumor cells. PD-L1- positive inflammatory cells were also seen in tumors of 2 (1.6%) cases. There was no significant relationship between PD-L1 expression and survival times (p= 0.690). In 57(45.6%) cases, FOXP3- positive lymphocytes were detected. The number of FOXP3-positive cells ranged between 1 and 55/HPF. There was no statistically significant correlation between the survival times and presence of Tregs (p=0.793). Twenty-two cases (17.6%) were evaluated as HER2-positive. There was a statistical relationship between HER2-positivity and perineural invasion (p=0.006). Statistical significance between survival and some prognostic factors such as nodal metastasis (p=0.004), pT stage (p<0.01) and presence of perineural invasion (p=0.010) was determined. Conclusion: This study has demonstrated that the PD-L1 positivity was not effective on gastric tumorigenesis. We have found a positive correlation between the presence of Treg inflammatory cells and PD-L1 expression. But this relationship could not be proved by statistical analyses. However since PD-L1 expression was detected in only 4 cases, these findings should be confirmed in larger series.

Keywords

• gastric carcinoma
• pd-l1
• foxp3
• her2
• prognosis