Missense mutation of STEAP2 was the main type of genetic alteration, and mutation in E390 of the ferric oxidoreductase domain, which was detected in uterine corpus endometrial carcinoma (n = 3), colorectal adenocarcinoma (n = 1), and skin cutaneous melanoma (n = 1), induced a frameshift mutation of the STEAP2 gene, translation from glutamate (E) to another amino acid at position 390 of the STEAP2 protein, and subsequent STEAP2 protein truncation. Here, STEAP2 is linked to colorectal adenocarcinoma.