PC gene therapy is mainly based on target genes, such as p16INK4A/CDKN2A, p21CIP1/WAF1, p14ARF, K-ras, LSM1/CaSm, HER-2/EerB-2, MDR1, BCRP, and VEGF. This evidence concerns the gene CDKN1A and pachyonychia congenita.