RPS6KB1 and melanoma: In addition, hyperphosphorylation of mTOR at its threonine Thr2446 and serine residues (Ser2448 and Ser2481) occurred both via the EGFR-ERK-S6K1 axis and the PI3K/AKT axis [48] and is related to growth in various types of cancers and melanoma [49].