ACE and colorectal carcinoma: The classical RAS consists of various axes, including the renin/angiotensin-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II type 1 receptor (AT1R) axis, whose components have been widely identified to play a role in different malignancies, such as ovarian carcinoma (Suganuma et al., 2005), renal cancer (McKay et al., 2015; Zheng et al., 2015), colorectal carcinoma (Neo et al., 2010), and breast cancer (Zhao et al., 2010).