Kao et al. have analyzed the pathogenesis of multiple myeloma and PCa and developed a model, in which cytokines (such as IL-6, IGF-1 and VEGF) and immune suppression caused by multiple myeloma are responsible for an increased progression of prostatic intraepithelial neoplasia as a risk factor to detectable stages of PCa4. This evidence concerns the gene IGF1 and prostate intraepithelial neoplasia.