As presented in Fig. 1B, OPN3 had significantly high expression in most cancer types, including BRCA, COAD, LAML (acute myeloid leukaemia), OV (ovarian serous cystadenocarcinoma), PAAD (pancreatic adenocarcinoma), READ (rectum adenocarcinoma), THYM (thymoma), UCEC (uterine corpus endometrial carcinoma), CESC, LUAD (lung adenocarcinoma), SKCM (skin cutaneous melanoma) and UCS (uterine carcinosarcoma), while OPN3 was expressed at low levels in LGG (brain lower grade glioma) and TGCT (testicular germ cell tumours). This evidence concerns the gene OPN3 and rectum adenocarcinoma.