Interestingly, while it has been shown that ERG-positive PC cells tend to express MAOA at a relatively lower level compared to ERG-positive cells (47), the fact that clorgyline inhibits the growth of both ERG-positive VCaP and ERG-negative LNCaP cells (48) suggests that MAOA could be a valid target in multiple types of PC even with varied levels of MAOA. The gene discussed is ERG; the disease is pachyonychia congenita.