[Dynamics of DNA content during the induction of epithelial tumors of the nasal cavity and paranasal sinuses in rats]. 
The data obtained with the use of microspectrophotometric studies of nuclear DNA in the process of induction and development of epithelial tumours of nasal cavity and paranasal sinuses in albino mongrel rats are analyzed.  Exponential increase of the DNA accumulation index in the process of neoplasm induction is observed.  A jump-like increase of the DNA accumulation index with relatively uniform values is established in the normal tissues, then in the metaplastic and dysplastic epithelia and in benign tumours as well as in the malignant tumours.