According to additional studies in the area where PIN develops, PIN cells can attract macrophages by secreting intercellular adhesion moleculeand CCL2, and these recruited macrophages can stimulate ERK and JNK signals in PIN cells by secreting CXCL1, which stimulates PIN cell proliferation (Fig. 5) [156]. This evidence concerns the gene CXCL1 and prostate intraepithelial neoplasia.