Torres et al. [49] proposed a prognostic biomarker panel for PC comprising five serum cytokines, including CD80, prokineticin 1 (PK1), IL-29, neuregulin 1 (NRG1-beta1), and thymidine phosphorylase (PDECGF), based on the association between their serum concentrations and a poor prognosis. Here, TYMP is linked to pachyonychia congenita.