Feulgen hydrolysis profiles and acid-labile DNA in oral squamous cell carcinoma

The full Feulgen hydrolysis profiles of healthy and malignant oral epithelial cells were compared by measuring the staining density of nuclei using microdensitometry after varying hydrolysis times. Malignant nuclei contained significantly increased levels of acid-labile DNA. The relative amounts of the rapidly hydrolysable fraction were compared after 5 min hydrolysis for exfoliating epithelial cells from healthy oral mucosa, healing chronic ulcers and squamous cell carcinomas. Although the latter exhibited a wide range of values, analysis of variance showed significant differences (P < 0.05) between healthy control and ulcer groups compared to oral carcinoma. The relative proportion of highly acid-labile DNA in malignant nuclei showed a significant positive correlation with mitotic score (P < 0.01) but no significant correlation with nuclear area. It was concluded that since the susceptibility of DNA to acid hydrolysis probably reflects functional differences in nuclear activity between cells, estimation of the highly acid-labile fraction may have diagnostic and/or prognostic value.