Following its initial discovery, ABCB5 has been shown to be highly expressed by cancer stem cells in various human malignancies including malignant melanoma [9,17,18,19,20], colorectal cancer [21,22], hepatocellular carcinoma [23], breast cancer [24], non-small cell lung cancer [25], oral squamous cell carcinoma [26], glioblastoma [27], and Merkel cell carcinoma [28], where it is associated with tumor growth, invasiveness, chemoresistance and recurrence [20,29,30]. This evidence concerns the gene ABCB5 and cancer.