SQSTM1 and squamous cell carcinoma: TWIST1 is a helix–loop–helix transcription factor that together with SNAIL and SLUG dictates activation of EMT.38, 39 Autophagy deficiency in squamous cell carcinoma (SCC) and melanoma results in stabilization and upregulation of TWIST1, which, in turn, induces the activation of EMT in vitro and promotes tumor growth and metastasization in mice.31 TWIST1 stabilization in autophagy-deficient cancer cells is mediated by the accumulation of sequestome-1 (SQSTM1/p62), an ubiquitin-binding protein which is a target of cargo-selective autophagy.