CCR6 and neoplasm: We further analyzed the frequency of CCR6+Tregs and CCR6−Tregs at day 10 or 28 (defined as early and late stage respectively) and found that the CCR6−Treg frequency in TILs (6.1%) at late stage of tumor was equal to that (5.9%) at early stage of tumor; while the frequency of CCR6+Tregs in TILs (12.5%) at late stage of tumor was significantly higher than that (5.7%) at early stage of tumor (Fig. 1d, p<0.05).