In this study, mutations in the genes ARID1A, APC, ERBB4, NCOR1, PDGFRA, ATM, and CDKN2A were either non-recurrent or of very low frequency, while none of the 14 sequenced EP tumours harboured mutations in the genes HRAS, EGFR, or RB1. This evidence concerns the gene HRAS and neoplasm.