TP53 and neoplasm: TP53 is mutated in up to 70% of oesophageal cancers and the loss of TP53 function may also sensitise the tumour selectively to the inhibition of ATR through synthetic lethality, although it should be noted that 15–30% of patients aged over 70 may carry heterozygous TP53 mutants in normal oesophagus [18–20].