allow pooling of relative RNA expression levels among all samples. CT values for target genes and the internal reference gene were converted to relative expression levels using the standard curve method, which compares each experimental sample with a calibrator reference RNA sample whose RNA level for each probe is defined as 1 (Wong and Medrano, 2005). PCR cycles were: 95°C for 10 minutes, then 40 cycles of 95°C for 15 seconds and 60°C for 30 seconds.
