CD44 and colorectal carcinoma: In the CRC setting, CD44 variant-positive cancer stem cells have been demonstrated to be resistant to redox stress in the tumor microenvironment by enhancing the ESRP1-CD44v-xCT-GSH (cysteine/glutamate antiporter) axis [35, 38, 39], and thus these cells are almost unaffected by selective pressure determined by oxygen deprivation and anti-cancer treatments Another interaction involving beta-catenin in CRC regards CD200, a membrane protein that characterizes neoplastic cells with cancer stem properties [40].