In sample P2-TN1, the only predicted driver point mutation was a deleterious mutation in the tumour suppressor gene TP53, and this was detected in both DCIS and invasive compartments and was also present in all cancer regions of the second PBC, P2-TN2, consistent with an early onset in the development of this cancer (phylogenetic tree; Fig. 3e,f). Here, TP53 is linked to cancer.