The locally rearranged subtype is characterised by focal amplifications of genes that can be therapeutically targeted, such as ERBB2 (also known as HER2), FGFR, PIK3CA and PIK3R3. Despite being altered in only ≈2% of cases, ERBB2 drives important biological signalling in PC, is associated with lung and brain dissemination (as opposed to liver metastasis as the most common metastatic site) and can be targeted using widely used ERBB2 inhibitors [35,36,37]. Here, ERBB2 is linked to pachyonychia congenita.