IGFBP3 and prostate carcinoma: In the prostate cancer cells, wild type (wt) IGFBP-3 was equally distributed in the cytoplasmic and nuclear fractions, whereas, mutants of IGFBP-3 at NES, Leu 197 and Leu 200 demonstrated an increased expression of IGFBP-3 in the nuclear fraction in comparison with the wt.