ABCG2 and Familial prostate cancer: Furthermore, since p75NTR is also present in CSCs and is co-expressed with stemness markers, such as CD133 in LSCC [16], and with ABCG2 in tumors involving different organs, and also in primitive hepatic and prostatic cancers [23], the possibility that p75NTR might be a novel CSC marker of LSCC has also been explored.