In irradiated tumours the combined effects of sustained increased expression of AMPK-p53-p21cip1/p27kip1 pathway, that is shown to lead to inhibition of cell cycling, and inhibition of Akt-mTOR-4EBP1 pathway, known to lead to gene transcription and translation, may be capable of mediating an effective anti-proliferative action in those tumours, which may be adequate to mediate the cytotoxic action of IR [13]. This evidence concerns the gene CDKN1A and neoplasm.