FOXP3 and cancer: Previous studies have shown that FOXP3 expression is associated with a poor prognosis in patients with various cancers.46–52 On the other hand, a meta-analysis on gastric cancer described that tumoural Foxp3-positive TILs were associated with poor survival, whereas extratumoural Foxp3-positive T-cell invasion was associated with better survival, suggesting that FOXP3 T cells have opposite functions in the intra- and extratumoural environments.53 In fact, in LCNEC patients, stromal FOXP3 expression on TILs has been reported to be a favourable prognostic factor.53