ARMCX1 and neoplasm: Overexpression of ARMCX1 suppresses the anchorage-dependent and -independent growth of colon cancer cells12, while knockdown of ARMCX1 accelerates the hepatocarcinogenesis in mice13, indicating the tumor suppressive roles of ARMCX1. Thus, it has been an urgent task to determine the functions of ARM repeat-containing proteins in the aggressiveness and progression of tumors.