Hewitt KM et al reported that methylation of the HRPT2/CDC73 promoter had been detected in 2/11(18%) of PC but 0/37 of sporadic PA tumors [25] This result suggested epigenetic mechanisms including methylation of DNA, histone modifications, or RNAs interfering may be involved in the inactivation of HRPT2/CDC73 gene [26]. The gene discussed is CDC73; the disease is pachyonychia congenita.