Relative SHBG Gene Expression (Total and Promoter-specific) Among Human Cancer Cell Lines and Normal Tissues. Quantitative RT-PCR (qPCR) was performed on total cellular RNA samples isolated from the indicated cell lines (in triplicate) and from normal tissues (in duplicate), using primers specific for SHBG exons 1L and 2, 1T and 2, 1N and 2, or exons 2 and 3 as described in the Experimental Procedures. Each sample was analyzed by qPCR in triplicate (nine total measurements for each cell line per assay, six for each tissue). Ct values represent the number of cycles required to reach an arbitrary point on the exponential part of the qPCR curves. "Normalized Ct" values for each of the 1L-2, 1T-2, 1N-2 and 2–3 assays represent mean Ct values for a given sample, normalized to the mean GAPDH Ct value for that same sample. SD: Standard deviation, calculated from the averages of the total measurements. Relative transcript abundance is presented as the ratio of Ct means; an arbitrary value of 1 is assigned to MCF-7.