As depicted in Fig. 1A, the expression of SLC31A1 is significantly lower in certain tumours than in the adjacent normal tissues, including cholangiocarcinoma (CHOL), kidney renal clear cell carcinoma (KIRC), kidney renal papillary cell carcinoma (KIRP), liver hepatocellular carcinoma (LIHC), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), thyroid carcinoma (THCA), and prostate adenocarcinoma (PRAD). The gene discussed is SLC31A1; the disease is prostate adenocarcinoma.