Nuclear Dna Content As A Criterion Of Malignancy In Salivary Gland Tumours Of The Oral Cavity

Deviation from the normal number of chromosomes is a characteristic feature of most malignant tumours and they are often great enough to cause changes in the nuclear content of DNA detectable by means of quantitative cytochemical methods. In malignant tumours of the parotid gland we have found that the nuclear DNA content of these tumour cells, as determined by quantitative cytophotometry, was increased by 25 to 50% above the normal value. It was therefore believed that cytophotometric DNA analysis could add further information as to the question of malignancy of salivary gland tumours where morphologic methods are uncertain. Regarding the tumours of the oral cavity, the question of malignancy is still a matter of controversy in two types of tumour, namely monomorphic adenoma and highly differentiated mucoepidermoid tumour. The cytophotometric DNA analysis of the present study showed that the: nuclei of the monomorphic adenoma cells had identical DNA values with the normal control cells. The highly differentiated mucoepidermoid tumour cells, on the other hand, exhibited higher DNA values, which were comparable with those of malignant parotid tumour cells. This adds fürther support to the idea that the monomorphic adenomas, despite the high cellularity are benign tumours, while the highly differentiated mucoepidermoid tumour should be considered as a malignant tumour.