For example, with combined genomic/epigenomic subgrouping of PC data from the Cancer Genome Atlas, nearly three-fourths of all PC cases could be categorized into one of four gene fusion groups (ERG, ETV1, ETV4, and FLI1) or three gene mutation groups (SPOP, FOXA1, and IDH1) [4]. Here, IDH1 is linked to pachyonychia congenita.