Part of them have been documented to be tumor promoter genes of PC, such as GABRP, CEACAM5, CEACAM6 and CST1 (Takehara et al., 2007; Govindan et al., 2009; Riley et al., 2009; Jiang et al., 2015). The gene discussed is CST1; the disease is pachyonychia congenita.