In PC clusters, high levels of CXCR4, CD319 (PC3), and CD117 (PC6) were associated with longer OS, in contrast to high levels of CD289 (PC2), CD28 (PC3), and IRF-4 and low levels of CD329 (PC4) and CXCR4 (PC7) related to short OS (Figure 7). The gene discussed is CD28; the disease is pachyonychia congenita.