The ALDH1A subfamily has largely been associated with elevated expression in cancer tissues, and in particular in cancer stem-like cells ALDH1A1 is a frequently expressed enzyme in stem cells and target for therapeutic intervention, however, other isoforms such as 1A2, 1A3, 2, 3A1 and 7A1 have drawn significant attention in the recent years due to their involvement in various pathophysiological conditions. The gene discussed is ALDH1A1; the disease is cancer.