Molecular basis : Caused by somatic mutation in the KRAS protooncogene, GTPase, gene (KRAS, 190070.0002); Caused by somatic mutation in the fibroblast growth factor receptor 3 gene (FGFR3,
134934.0013); Caused by somatic mutation in the RB transcriptional corepressor 1 gene (RB1, 614041.0009); Caused by somatic mutation in the HRAS protooncogene, GTPase, gene (HRAS, 190020.0001);