As CD39 could be used as a proxy marker for the subsets of activated Treg accumulating in colon tumors, we extended our studies to a set of 44 consecutive patients, and used flow cytometry to identify CD39+ Treg in tumors, unaffected tissue, and blood (see Additional file 1: Figure S5 for gating strategy). The gene discussed is ENTPD1; the disease is colonic neoplasm.