TP53 and pachyonychia congenita: Consistent with previous reports about PC tumourigenesis [18, 19], we observed ETS fusions and mutations or loss of TP53 to be early (clonal) events (Figure 2 and supplementary Table S3, available at Annals of Oncology online), PTEN a later event (60% clonal), and mutations or deletions of chromatin modifiers (KMT2C, KMT2D and CHD1) as a later (subclonal) event (Figure 2).