In one of these tumours a single TP53 truncation mutation was present at about one-fifteenth the frequency of a single VHL frameshift mutation, implying that the TP53 mutation was an event that occurred secondarily to an initiating VHL mutation and that it resulted in the formation of a VHL/TP53 double mutant sub-clone of the tumour cell population. This evidence concerns the gene TP53 and neoplasm.