RB1 and pachyonychia congenita: Need for better molecular biomarkers: Genomic alterations in TP53, RB-1, PTEN, and TMPRSS2-ERG fusions are often found in aggressive traditional PC and other NEPCs.6 Determining LCPC-specific genetic/epigenetic evolution may help predict a patient’s future trajectory.3 New biomarkers might identify large-cell NE differentiation before advanced-disease develops.