We examined the expression of ADGRG2 in 33 kinds of cancers using TCGA (tumor and normal data) cohorts (Figure 1A), resulting in most cancer patients’ ADGRG2 being down-regulated, while it was preeminently higher in four types of cancer, including cholangiocarcinoma (CHOL), kidney renal clear cell carcinoma (KIRC), liver hepatocellular carcinoma (LIHC), and thyroid carcinoma (THCA). This evidence concerns the gene ADGRG2 and cholangiocarcinoma.