ERBB4 and pachyonychia congenita: In an analysis of matched primary GC, GC-PC, and non-neoplastic gastric tissue samples, Lim et al. documented the enrichment within GC-PC of mutations in metastasis-associated genes (including L1CAM and TGFBR1), along with druggable genes such as BRAF, ERBB4, FLT3, PIK3CA, and PIK3C2B [41].