In summary, our data suggest that exposure to insulin and potentially IGF-I reduced the frequency of formation of fusion products whereas both hyperglycemia and IGFBP-2 increased the number of TMPRSS2-ERG gene fusions and these factors could contribute to the negative impact that obesity has on PCa progression. The gene discussed is IGFBP2; the disease is obesity due to melanocortin 4 receptor deficiency.