RAB13 and bile duct cancer: Various RAB genes have been linked to tumors, including RAB27A [39], which serves as a predictive indicator for pancreatic ductal adenocarcinoma; RAB13 and RAB3D, which are elevated in pan-cancer [40,41]; and RAB1A and RAB6A, which have significant functions in rectal cancer and bile duct cancer [42,43], respectively.