However, in contrast to TRP53-deficient mice which all develop tumours prior to 300 days of age (in the absence of an engineered oncogenic driver), the PUMA-deficient as well as PUMA/NOXA double-deficient mice do not develop cancer spontaneously on a C57BL/6 genetic background [188, 191]. This evidence concerns the gene PMAIP1 and neoplasm.