[Some measures of proliferative activity in normal and leukoplakic buccal mucosa (author's transl)]

In 29 patients, the DNA synthesis rate of clinically healthy buccal mucosa epithelium in comparison to benign buccal leukoplakias has been studied by in vitro-autoradiography. The proliferative activity has been determined by means of the 3H-labelling indices of basal cells (LBC) and suprabasal cells (LSBC) including the total of labelled epithelium cells and the quotient of LBC:LSBC as well. The progenitor compartment of both leukoplakic and normal buccal epithelium comprises the stratum basale and the adjacent 2-3 layers of suprabasal cells. Around 70% of the DNA synthesis of normal mucosa was found in the suprabasal nuclei of the progenitor compartment. In the leukoplakic mucosa, some displacement of the labelled nuclei in the progenitor compartment resulting in a statistically significant change of the quotient of LBC:LSBC in favour of LBC was determined. Moreover, the leukoplakic specimens showed a moderate decrease of the mean proliferative activity of the total of labelled epithelial cells which may be due to a diminished exfoliation of cornified cells from the hyper(ortho)keratotic surface. It is supposed that in chronic oral leukoplakias some variation of the steady state between renewal and desquamative loss of epithelial cells is operating as far as no precancerous condition is present.