STK11 and cancer: Several potential mechanisms proposed for its ability to suppress cancer in vitro and in vivo include: (a) activation of the LKB1/AMPK pathway, (b) induction of cell cycle arrest, and/or apoptosis, (c) inhibition of protein synthesis, (d) reduction in circulating insulin levels, (e) inhibition of the unfolded protein response (UPR), (f) activation of the immune system, and (g) eradication of cancer stem cells (Kourelis and Siegel, 2012).