In one study, patients with rectal adenocarcinoma (n = 64) who received preoperative radiochemotherapy showed high expression levels of different CSC markers—CD44, LGR5, CD166, and ALDH1—by immunostaining; additionally, in a Cox proportional hazards multiple regression model, ALDH1 independently predicted poor prognosis in patients with CRC who received radiochemotherapy [20]. The gene discussed is ALDH1A1; the disease is colorectal carcinoma.