ALDH1 is abundant in tumor samples from patients with CRC (21, 84), which can be used as a particular marker for CSCs of colorectal cancer (85), mainly including ALDH1A1, ALDH1B1, and ALDH1A3, are associated with poor prognosis and resistance to chemotherapy in colorectal cancer (86–88). The gene discussed is ALDH1A1; the disease is colorectal cancer.