TP53 and neoplasm: Along with the benefits of reversing ageing process and maintaining physiologic functions, anti‐tumour actions of NAM also have recently been addressed in various tumours by regulating SIRT1/2‐, p53‐, AKT‐ and poly (ADP‐Ribose) polymerase 1 (PARP1)‐dependent cascades [8, 9, 10, 11, 12].