The expression of TTC21A was significantly higher in CHOL (Cholangiocarcinoma), KIRC (Kidney Renal Clear Cell Carcinoma), KIRP (Kidney Renal Papillary Cell Carcinoma), LIHC (Liver Hepatocellular Carcinoma), PCPG (Pheochromocytoma and Paraganglioma), PRAD (Prostate Adenocarcinoma), READ (Rectum Adenocarcinoma), STAD (Stomach Adenocarcinoma) compared with that of normal tissues. Here, TTC21A is linked to pheochromocytoma-paraganglioma.