Furthermore, melatonin can decrease tumor cell proliferation and viability by inhibiting the negative feedback from the downstream effector of the PI3K/Akt (PKB) signaling pathway—mammalian target of rapamycin complex 1 (mTOR) [35,36] and modulate apoptosis [37,38]—and inhibit the GC/cGMP/PKG pathway [39]. The gene discussed is AKT1; the disease is neoplasm.