PSCA and neoplasm: At the prostate several biological processes (regulation of proliferation and cellular differentiation, mitogenic activity, secretory processes and tumor growth) are regulated and/or influenced by different growth factors, such as IGF (insulin growth factor), FGF (fibroblast growth factor), VEGF (vascular endothelium growth factor), transforming growth factors, metalloproteinases and PSCA (prostate stem cell antigen) (17–22).