An internal control target sequence is included in the
amplification reaction so that the amplification efficiency of the
telomerase products can be normalized. The intensity of ladder bands
within the area from 80 bp to 120 bp and of the internal control band
was measured on gel images using image analysis software (ImageJ
1.33u). Intensities of ladder bands of samples and the positive control
were standardized using the intensity of the internal control band in
their lanes after background subtraction of their heat-treated controls.