SHBG and Familial prostate cancer: To test whether absence of the SHBG protein in prostate cancer cell lines resulted from reduced translation due to a modulatory action of the 5′UTR sequences of exon 1A and 1B on the translation efficiency from the first ATG in frame of exon 2, LNCaP cells were transfected with several SHBG constructs with and without exon 1A and exon 1B 5′UTR sequences (Figure 5C).