The gene encoding this factor (IGF-I) consists of 6 exons that generate 3 different isoforms: IGF-IEa, IGF-IEb and IGF-IEc (30) and the IGF-IEc isoform is highly expressed during PCa and this has been directly related to an increase in proliferation mediated by the activation of the IGF-1R receptor in PCa epithelial cells (Figure 1C). The gene discussed is IGF1; the disease is posterior cortical atrophy.