Microspectrophotometric Dna Analysis of Malignant Salivary Gland Tumours

Abstract

Microspectrophotometric determinations of nuclear DNA quantity of Feulgen-stained cells were made in six selected malignant salivary gland tumours and compared to normal salivary gland tissue and human lymphocytes from peripheral blood. Two questions of methodical importance were investigated and it was found that no errors in the quantitative DNA determination were introduced as a result of the imprint technique and that the optimal duration of acid hydrolysis in the Feulgen staining procedure was 60 min. Microspectrophotometric DNA analysis of the six malignant salivary gland tumours showed nuclear DNA quantities which exceeded that of the normal control cells irrespective of the type of tumor and degree of differentiation. Furthermore, a much higher degree of intercellular variability with respect to the nuclear DNA content was found in the malignant tumour cell populations. The fraction of cell nuclei with DNA values exceeding that of normal cells varied according to the type of tumour, and the incidence was small in biological low grade malignant tumours and high in high grade malignant tumours. Thus the nuclear DNA content seems to be an objective parameter in grading the malignancy of salivary gland tumours.