Interestingly, in a separate pre-clinical study comparing the response of K, KL and KP GEMMs to phenformin, it was discovered that KL tumours showed a significant response to phenformin, while K and KP lung tumours remained resistant, thus demonstrating that Lkb1 inactivation determined sensitivity to phenformin (Shackelford et al, 2013a). This evidence concerns the gene STK11 and neoplasm.