SOX2 and neoplasm: Second, real-time QRT/PCR analysis using primer set that amplifies human mRNAs showed that after normalization to GAPDH mRNA level in each sample, compared to Sox2 mRNA level in scrambled peptide injected tumors, the expression level of Sox2 mRNA was decreased by 50% in IRIS-inhibitory peptide treated tumors (Figure 7B), suggesting that the regression measured is due to IRIS inactivation-induced decrease in the pool of TICs within the tumor.