STAT3 and cancer: Some constituents occurring in AR, e.g., gallic acid (Subramanian et al., 2016), catechin (Haratifar et al., 2014), and epicatechin (Kim et al., 2012), have been reported to exert anti-cancer effects by inhibiting STAT3 signaling (Leong et al., 2009; Shay et al., 2015; Phan et al., 2016).