Expression and its clinical significance of programmed death ligant 1 on CD3+ T cells in colorectal cancer / 中华消化杂志

ABSTRACT

Objective To study on the expression and clinical significance of programmed death ligant 1 (PD-1) in the development of colorectal cancer.Methods Flow cytometry (FCM) was used to detect and analyse the positive expression rate of PD-1 on CD3+ T cells in peripheral blood samples of 88 colorectal cancer patients and 74 healthy volunteers,and in sixpairs of tissue specimens (colorectal cancer tumor and adjacent normal tissues).Colon cancer tumor-bearing mice models were constructed by subcutaneous implantation of murine colon cancer cell line CT26,and the changes of positive expression rate of PD-1 on CD3+ T cells in spleens and transplanted tumor tissues were also detected by FCM in different time points during five,eight,11,14,17,20 days after the model was constructed.Finally,the experimental results were analyzed by t test or variance analysis.Results The positive expression rate of PD-1 on CD3+ T cells in peripheral blood of colorectal cancer patients was significantly higher than that in healthy volunteers ((29.25 ± 9.37) ％ vs (19.35 ± 7.37) ％,t =7.375,P＜ 0.01),and the positive expression rates were significantly increased in colorectal cancer patients with lower degree of differentiation,lymph node metastasis and higher Duke's stage.The positive expression rate of PD-1 on CD3+T cells was significantly higher in colorectal cancer tissues compared to adjacent normal tissues ((52.38±12.28)％ vs (24.72±4.78)％,t=5.143,P＜0.01).In the colon cancer tumor-bearing mice models,along with the growth of transplanted tumors,PD-1 positive expression rates on the CD3+T cells of tumor-bearing mice spleens and transplanted tumors showed a gradually rising tendency.From the eighth day to the 20th day after subcutaneous transplanted colon cancer cells,the average positive expression rate of PD-1 on the CD3+T cells of tumor-bearing mice spleens rose from (52.83±6.17)％ to (77.30± 6.84) ％,and the average positive expression rate of transplanted tumors rose from (60.43 ± 2.77)％ to (90.47±4.31) ％.Conclusion There is a correlation between the expression of PD-1 on mature T cell surface and the development of colorectal cancer,and the high specific expression of PD-1 may promote the invasion and metastasis of colorectal cancer.