In a), it is shown that there is no significant effect on normalization between the use of the two most stable genes and the three most stable genes. The discrepancies in expression levels of p16INK4a were statistically significant with ANOVA with the use of GAPDH, ACTB, EEF1A1 and RPLPO as individual normalizers, when compared with the use of the two most stable genes or the three most stable genes. Graph b), shows the expression levels of p16INK4a in cervical tissues using the combination of GAPDH and ACTB (obtained from the analysis involving individual Ct values) as the normalizer. The error bars indicate a 95% confidence interval; *, p<0.05; **, p<0.01; ***, p<0.0005; ****, p<0.0001.