MYC and neoplasm: Interestingly, an in vivo analysis of p53-dependent functions in Myc-induced lymphomas arising in Eμ-myc transgenic mice has indicated that apoptosis is the only p53 effector program that is selected against during tumour formation (Schmitt et al, 2002), suggesting that cell cycle checkpoint defects and genomic instability are by-products of p53 loss.