To investigate the potential effect of the TMPRSS2-ERG fusion protein on IGF1R gene expression, we employed two metastatic prostate cancer-derived cell lines with or without the chimera: the VCaP cell line, which expresses the chimeric protein in an endogenous manner, and the M12 cell line, which is devoid of the fusion protein. The gene discussed is TMPRSS2; the disease is Familial prostate cancer.