JAK1 and cancer: As the IFN-JAK1-STAT1 signalling cascade activates two key inducers of senescence14,31,32, p16Ink4a and p21Cip1, here we analyse whether cancer immune control requires the IFN-γ-dependent induction of the tumour-intrinsic p16Ink4a-CDK4/6-Rb1 and MDM-p53-p21Cip1 cell cycle regulation pathways to arrest those cancer cells that escape from cytotoxicity.