Expression Of B7-H2 In CD8~+T Cells In Colorectal Cancer Microenvironment And Its Clinical Significance

【Objective】To explore the expression feature and clinical significance of B7-H2 in CD8~+T cells in colorectal cancer microenvironment by detecting the expression level of B7-H2 on CD8~+T cells in the specimen of colorectal cancer patients and tumor bearing mice.【Methods】1.Fresh tissue samples including colorectal cancer tissues and paired adjacent non-tumor tissues collected from 25 patients with colorectal cancer treated in the First Affiliated Hospital of Suzhou University from March 2015 to February 2016,were digested by enzyme,ground and filtered to obtain single cell suspension.Then the expression level of B7-H2 on the infiltrating CD8~+T cells was detected by flow cytometry.The clinical significance of the expression was analyzed with medical records.2.Tumor bearing mice were sacrificed on the fifth day,tenth day,fifteenth day,twentieth day and twenty-fifth day after inoculation.The tumor tissues and spleen were extracted,ground and filtered to obtain single cell suspension.Flow cytometry was used to analyze the expression of B7-H2 on the CD8~+T cells in tumor tissues and spleen.【Results】1.The expression of CD8~+T cells(11.68±12.04%)in tumor tissues of colorectal cancer patients was significantly higher than that of adjacent non-tumor tissues(5.44±4.81%),p=0.0057.2.The expression of CD8~+T cells in tumor microenvironment was significantly correlated with the age of patients(p=0.0472)and staging(p=0.0414).The expression of B7-H2 on CD8~+T cells in tumor microenvironment was significantly higher than that in patients with colorectal cancer>60 years old.The expression of B7-H2 on CD8~+T cells in tumor microenvironment was significantly higher in the stageⅢ-Ⅳpatients than that in the stageⅠ-Ⅱpatients.No correlation with the patient’s gender or tumor location was discovered(p>0.05).3.The expression level of B7-H2 on CD8~+T cells in the tumor and spleen of mice both reached the highest level at the early stage of inoculation(at day 5),and then decreased,and then gradually increased.4.At the early stage of inoculation(at day 5)the expression of B7-H2 on the CD8~+T cells was higher in the tumor tissues than in the spleen.At the middle stage of inoculation(at day 10)the expression of B7-H2 on the CD8~+T cells was significantly lower in the tumor tissues than in the spleen.There was no significant difference in the tumor tissues and spleen at the late stage(at day 15、20、25).【Conclusion】In this study,it was found that the expression of B7-H2 on CD8~+T cells in tumor microenvironment was closely related to the progression of the disease.