RPS6KA2 and neoplasm: Meanwhile, the increase in the levels of phosphorylated RPS6KA1 could lead to the activation of RPS6KA family members, specifically, RPS6KA1 and RPS6KA3 (RSK2), which support cell proliferation and growth while RPS6KA2 (RSK3) and RPS6KA6 (RSK4) play roles in tumor suppression, cell cycle arrest, and apoptosis [48,49].