GAPDH and neoplasm: With reference to stability of expression in both normal and in tumor samples, the lowest RNA transcription ranges (i.e Ct 75°quantile-Ct 25°quantile) were associated withPOLR2A (normal = 0.73; tumor = 0.69) and rRNA18S (normal = 0.69; tumor = 0.93), whereas the highest ranges were detected for GAPDH (normal = 1.8; tumor = 2.2) and RPLP0 (normal = 1.71; tumor = 1.84).