Expression And Clincopathological Significance Of TIGIT And PD-L1 In Colorectal Adenocarcinoma Tissues

ObjectiveTo detect the expression of TIGIT,CD155 and PD-L1 in colorectal carcinoma tissues,and analyze the relationship between the expression levels of TIGIT,CD155,and PD-L1 with clinicopathological characteristics and microsatellite status;to explore the influence of TIGIT,CD155 and PD-L1 expression on the prognosis of patients,in order to find a new target for tumor immunotherapy or a biomarker for predicting prognosis;to further analyze whether there is a relationship between the expression of TIGIT and PD-L1 in colorectal carcinoma tissues,and to provide theoretical basis for in-depth research of the application of TIGIT inhibitors in colorectal carcinoma(or)combined with PD-L1 inhibitors.MethodsA total of 140 cases of colorectal adenocarcinoma samples(including 73 cases of colon and 67 cases of rectum)were collected from the Department of Pathology of the 940 th Hospital of the Joint Logistic Support Force from January 2015 to January 2016,and select 40 samples of normal intestinal mucosal tissue adjacent to cancer as controls(the shortest distance between the sample location and the tumor tissue>5cm),the expression levels of TIGIT,CD155 and PD-L1 in colorectal carcinoma tissues were detected by immunohistochemical staining,Clinical data were reviewed and patients were followed up.IBM SPSS Statistics 25.0 software was used to analyze and process the data.Results1.The positive rates of TIGIT in colorectal carcinoma tissue and adjacent tissues were79.3%(111/140)and 15.0%(6/40),and the difference was statistically significant(P<0.05).The expression of TIGIT was significantly correlated with the degree of differentiation(P=0.006),lymph node metastasis(P=0.002),distant metastasis(P=0.045),and pTNM stage(P=0.001),but had no statistical significance with infiltration depth,TP53,MSI status,etc(P>0.05).2.The average 5-year PFS of TIGIT-negative,weak-positive and strong-positive patients was 65.167 months,55.071 months and 38.101 months,respectively,and the difference was statistically significant(P<0.05).3.The positive rates of CD155 in colorectal carcinoma tissue and adjacent tissues were82.1%(115/140)and 25.0%(10/40),and the difference was statistically significant(P<0.05).The expression of CD155 was significantly correlated with the degree of differentiation(P=0.030),lymph node metastasis(P=0.001)and pTNM stage(P=0.001),but had no statistical significance with infiltration depth,distant metastasis,MSI status,etc(P>0.05).4.The average 5-year PFS of CD155-negative,weak-positive and strong-positive patients was 63.056 months,60.353 months and 37.769 months,respectively,and the difference was statistically significant(P<0.05).5.The positive rates of PD-L1 in colorectal carcinoma tissue and adjacent tissues were33.6%(47/140)and 0%(0/40),and the difference was statistically significant(P<0.05).The expression of PD-L1(T)in colorectal carcinoma tumor cells was significantly correlated with lymph node metastasis(P=0.010),distant metastasis(P=0.016),and pTNM stage(P=0.007),but had no statistical significance with differentiation degree,TP53,MSI status,etc(P>0.05).The expression of PD-L1(I)in the interstitium of colorectal carcinoma is related to lymph node metastasis(P=0.017)and pTNM staging(P=0.015),but is not statistically significant with distant metastasis,TP53,MSI status,etc.(P>0.05).6.The average 5-year PFS of PD-L1(T)negative and positive patients was 54.555 months and 42.178 months,respectively,suggesting that PD-L1(T)positive patients had a poor prognosis(P<0.05);The average 5-year PFS of PD-L1(I)negative and positive patients was 43.675 months and 55.095 months,respectively,suggesting that PD-L1(I)positive patients have a good prognosis(P<0.05).7.TIGIT and PD-L1(T)expression were positively correlated(r=0.441,P=0.000);TIGIT and PD-L1(I)expression had no correlation(r=-0.049,P=0.567).Conclusion1.The expression of TIGIT is related to the differentiation and progression of colorectal carcinoma.TIGIT-positive patients in colorectal carcinoma tissues have a short progression-free survival and poor prognosis.2.The expression of CD155 is related to the differentiation and progression of colorectal carcinoma.CD155-positive patients in colorectal carcinoma tissues have a short progression-free survival and poor prognosis.3.The expression of PD-L1 is related to the progression of colorectal carcinoma.PD-L1(T)-positive patients in colorectal carcinoma tissues have a short progression-free survival and poor prognosis;PD-L1(I)-positive patients in the interstitium of colorectal carcinoma have a long progression-free survival and good prognosis.4.The expression of TIGIT and PD-L1 in colorectal carcinoma is positively correlated.