The expression patterns of immunosuppressive molecules on regulatory T (Treg) cells have not been elucidated in non-small-cell lung cancer (NSCLC) patients. In this study, a total of 88 patients including 53 patients with NSCLC, 17 patients with lung non-malignant diseases, and 18 healthy volunteers were enrolled. Increased number of total CD4(+)CD25(+)FoxP3(+) Treg cells and elevated expressions on the surface of several inhibitory molecules including CTLA-4, LAG-3 and PD-1 have been observed in the peripheral blood of NSCLC patients. We found that intratumoral Treg cells from NSCLC patients express the highest levels of co-inhibitory molecules compared to Treg cells isolated from tumor adjacent tissues or from peripheral blood of cancer patients, which is in consistent with the enhanced immunosuppressive function of these co-inhibitory molecules. Moreover, the number of Treg cells and their functional surface molecules increased during the progression of lung cancer. Elevated plasma levels of TGF-β and IL-10 in NSCLC patients were also observed in NSCLC patients compared to that in healthy volunteers. Our findings further support the role of Treg cells in the tumor microenvironments in NSCLC patients.
Keywords: Regulatory T cells; immunosuppressive molecules; non-small-cell lung cancer; tumor-infiltrating lymphocytes.