Although, no significant correlation was observed between serum CTLA-4 levels and FoxP3 expression in either interstitial lymphocytes or tumor cells, FoxP3 expression in interstitial lymphocytes was strongly correlated with the CTLA-4 IHC score of interstitial lymphocytes (R = 0.387, P = 0.01, Fig. 4c). Here, FOXP3 is linked to neoplasm.