We used subcellular fractionation to detect both α- and β-subunits in the nucleus of both DU145 and 22Rv1 prostate cancer cells and showed by immunofluorescence microscopy that the α-subunit of nuclear IGF-1R is responsive to IGF-1R inhibition, analogous to previous results for the β-subunit [11]. Here, IGF1R is linked to Familial prostate cancer.