CTSB and cancer: Opposed to effects on CTSB and as expected based on our previous observations (Dhar et al., 2016, 2017), MTA1 negatively regulates E‐cad expression in primary tumor, a hallmark of EMT associated with metastasis (Figiel et al., 2017), indicating the impact of MTA1 in the process of EMT and cancer cell ability to migrate to distant sites.