ALDH1-positive cells have CSC-LC characteristics, such as the ability to self-replicate and to form tumors, so a number of researchers have used ALDH1 enzymatic activity as a CSC marker in many different types of cancer, including lung, liver, pancreas, prostate, bladder, breast and malignant melanoma [42]–[46]. Here, ALDH1A1 is linked to melanoma.