The expression of BTN3A1 in tumor and adjacent normal tissues was analyzed in TIMER database containing TCGA data, and the results showed that BTN3A1 expression was significantly higher in tumor samples of cholangiocarcinoma (CHOL), esophageal carcinoma (ESCA), head and neck squamous cell carcinoma (HNSC), kidney renal clear cell carcinoma (KIRC), kidney renal papillary cell carcinoma (KIRP), liver hepatocellular carcinoma (LIHC), and stomach adenocarcinoma (STAD), compared to their counterpart normal tissue controls (Fig. 1A). This evidence concerns the gene BTN3A1 and cholangiocarcinoma.