DPP4 and colonic neoplasm: Previous research studies have reported thatcertain subpopulations in colon cancer express distinct surface biomarkers,including CD133, CD44, and CD26, which are indicative of stem cell-likeproperties.5,40,41 To isolate colon CSCs in our study, we used CD133 and CD44 surfaceantigens, which have previously been characterized as reliable markersfor identifying CSCs.31,42