The frequency and expression of CD39 and LAP are significantly increased by intratumoral FOXP3+ Treg. (A, B) The fraction of CD39+ cells in FOXP3+ TIL-Treg and their CD39 expression levels (MFI) were compared with those in FOXP3+ PBL-Treg isolated from 10 HNC patients. (C, D) Similarly, the frequency and expression levels of LAP+ cells in FOXP3+ TIL-Treg was compared with those in FOXP3+ PBL-Treg isolated from HNSCC patients (n=10). (E, F) Representative flow cytometry analysis for CD39 (E) and LAP (F) expression in the FOXP3+ or FOXP3− CD4+ TIL and PBL isolated from one HNSCC patient. The numbers represent the percentage of CD39+ and LAP+ cells in CD4+ T cells for each quadrant, and the percentage values represent the fraction of CD39+ or LAP+ cells in FOXP3+CD4+ T (top right) or in FOXP3−CD4+ T cells (top left).