Correlation between PD-L1 protein expression and number of CD8+infiltrating lymphocytes and predictive value of prognosis in patients

Lyu Huiqing; Shen Hongchang; Zhan Bo; Wang Weibo

doi:10.3969/j.issn.1671-6450.2025.05.004

Abstract：Objective To analyze the correlation between PD-L1 protein expression and the number of CD8+infil-trating lymphocytes(TILs)in gastric cancer and its predictive value for patient prognosis.Methods 163 gastric cancer pa-tients treated in our hospital from January 2020 to December 2022 were selected to analyze the correlation between PD-L1 and CD8+TILs,as well as the relationship between PD-L1,CD8+TILs expression and clinical characteristics.The patients were followed up until June 2024,and their overall survival(OS)was recorded.Cox regression analysis was used to identify risk factors for prognostic mortality in gastric cancer patients,and Hosmer Lemeshow and ROC curve analysis models were used to assess the predictive value of prognostic mortality in gastric cancer patients.Results 67 cases showed positive ex-pression of PD-L1 and 96 cases showed negative expression;69 cases of high-density expression and 94 cases of low-den-sity expression of CD8+TILs in gastric cancer patients;According to Kendall's tau-b analysis,there was a negative correla-tion between PD-L1 expression and CD8+TILs expression in cancer patients(r=0.211,P=0.007).There were statistically significant differences(P＜0.05)in TNM staging,differentiation degree,infiltration depth,tumor residue between the PD-L1 positive group and the PD-L1 negative group;There was a statistically significant difference in TNM staging between the CD8+TTLs high-density group and the CD8+TILs low-density group(P＜0.05).All patients were followed up until June 2024,with 23 deaths and 140 survivors.The Kaplan Meier curves of PD-L1 positive and PD-L1 negative groups,CD8+TILs high-density group,and CD8+TILs low-density group were compared and statistically significant(Log Rank(Mantel Cox)x2=31.282,10257,P＜0.001,P=0.001).According to survival function Cox regression analysis,tumor diameter ≥ 5cm,infiltration depth(T3-T4),lymph node metastasis,tumor residue,and PDL1 protein(positive)are risk factors for the prog-nosis of gastric cancer patients(P＜0.05),while differentiation degree(medium high differentiation)and CD8+TILs(high density)are protective factors for the prognosis of gastric cancer patients(P＜0.05).The Hosmer Lemeshow test was used to construct a predictive model for the prognosis of gastric cancer patients based on risk factors.The results showed a chi square(x2)of 3.981 and a P-value of 0.895.ROC curve analysis showed that the AUC of the logistic regression model for predicting the prognosis and mortality of gastric cancer patients was 0.945,the Youden index was 0.782,the sensitivity and specificity were 903％ and 87.9％,respectively,and the accuracy was 90.8％.Conclusion High PD-L1 positive expres-sion and low CD8+TILs density are closely related and are independent risk factors for prognosis and mortality in gastric cancer patients.The logistic regression model constructed through risk factors has good predictive value for the prognosis of gastric cancer patients.