Analyses of prostate tissues obtained from both low and high grade PCa patients show that WSX-1 is expressed mainly by CD11c+ myeloid dendritic cells and monocytes/macrophages population, CD4+ and, to a lesser extent, by CD8+ immune cells infiltrating PCa stroma or homing prostate draining lymph nodes and also by endothelial cells, thus suggesting that exogenously administered IL-27 could affect the local tumor microenvironment. The gene discussed is CD4; the disease is posterior cortical atrophy.