Ct values for the gene of interest and GAPDH are inserted into a modified version of the ????Ct equation (Applied Biosystems Prism??? 7700 Sequence Detection System User Bulletin #2), which is used to calculate a GAPDH normalized relative cDNA level for each specific cDNA. The ????Ct equation is as follows: relative quantity of nucleic acid template=2????Ct=2(??Cta-??Ctb), where ??Cta=Ct target???