Furthermore, it has been reported that some important tumor suppressor genes such as PTEN (Yang et al. 2018) and SMAD4 (Cheng et al. 2018) are also targets of miR-224, which does not contradict our idea that miR-224 can control CRC progression partly through BTRC-mediated Wnt/β-catenin signaling pathway. Here, SMAD4 is linked to colorectal carcinoma.