FBXW7 and glioblastoma: Furthermore, studies have revealed that ubiquitin-mediated protein degradation is an effective mechanism by which GBM cells regulate the expression of the MYC protein and inhibit the function of MYC [18] Currently known E3 ubiquitin ligases that directly target MYC include F-box and WD repeat domain containing 7 (FBXW7) [18], F-box and leucine-rich repeat protein 3 (FBXL3) [19], and the carboxyl terminus of HSC70-interacting protein (CHIP) [20].