STK11 and cervical cancer: Hsieh et al. and Xiao et al. showed that metformin could reduce p53, activate LKB1 and AMPK, and inhibit mTOR via the inhibition of HPV, resulting in induced apoptotic HeLa and MS571 cell death, whereas cervical cancer cells both HPV- and LKB1-negative were less sensitive to metformin [50,51].