Abstract:

Objective To explore the expression and functions of MDSC（myeloid⁃derived suppressorcell）and its immunosuppression for T cells in patients with TSCC（tongue squamous cell carcinoma）. Methods Peripheral blood samples were collected from 40 patients with TSCC and 51 healthy controls. Flow cytometry wasused to detect the proportion of MDSC in peripheral blood and its influence on the proliferation function of CD4+ Tand CD8+ T cells，and the proportion of MDSC in fresh tongue carcinoma specimens was further detected. Results Compared with healthy controls，the proportion of MDSC in TSCC patients significantly increased，and majority ofthese cells were Polymorphonuclear⁃MDSC（PMN⁃MDS）. These MDSCs were able to suppress the proliferation of Tcell，which was dependent on the elevated reactive oxygen species（ROS）level. The proportion of MDSC in thetumor tissues also was higher than that in the adjacent tissues（P < 0.05），which mainly were also PMN⁃MDSCs.Conclusion MDSC may play an important immunosuppressive role in tumor microenvironment of TSCC depend⁃ing on ROS increasing.

Key words: myelin?derived inhibitory cells（MDSC）, tongue squamous cell carcinoma（TSCC）, im?
munosuppression