After integrating TMB data and MMS22L expression in pan-cancer, the TMB of 11 types of tumors (LUAD, COAD, READ, STES, KIPAN, STAD, prostate adenocarcinoma (PRAD), pheochromocytoma and paraganglioma (PCPG), ACC, and KICH) were positively related to MMS22L expression. The gene discussed is MMS22L; the disease is pheochromocytoma.