Quantitative determination of acid-labile DNA in cervical intraepithelial neoplasia

Using a modified Feulgen hydrolysis procedure and integrating microdensitometry, the acid-labile nuclear DNA in exfoliated cervical epithelial cells was quantified in a range of histologically confirmed cervical intraepithelial neoplasia (CIN), invasive cancer, and normal controls. The mean relative optical densities obtained for each sample group showed an increase from normal epithelium, through CIN grades, to invasive cancer. Although there was some overlap between groups, the difference in the overall mean values between the adjacent groups was statistically significant. The sensitivity of the test was 87.1% with a specificity of 99.2% and a predictive value of 99.5%, with no false negatives in the severe dysplasia and cancer groups. Quantitative data allows the threshold value to be altered to vary the sensitivity and specificity according to prevailing requirements. This suggests the possibility of using quantitative acid-labile DNA measurements to improve existing screening for cervical precancer.