SIK1 and neoplasm: As a tumor suppressor gene in NSCLC, LKB1 regulates AMPK, mTOR, VEGF, p53, p21/WAF1, SIK1, SIK3, and INSL4 to inhibit cell proliferation, cell differentiation, cell invasion, cell migration, tumor angiogenesis, and cell cycle arrest [85–89].