In addition, previous studies have indicated that metformin is involved in the tumor-suppressor pathway by inhibiting lipogenic pathways and stimulating liver kinase B1 (LKB1)-dependent activation of 5-AMP-activated protein kinase (AMPK), an inhibitor of cell proliferation via the mammalian target of rapamycin (mTOR) pathway [24, 25]. Here, STK11 is linked to neoplasm.