DNA analysis was performed by flow cytometry (FCM) in 59 cases of different types of pituitary adenomas who underwent microsurgery and were actively followed over a period of 3-6 years. Aneuploid DNA patterns were detected in 12 (20%) cases. Frequency of aneuploidy was highest in prolactin-secreting (36%) as compared to 17% in GH- and 7% in non-secreting adenomas. Some adenoma parameters valid for tumour growth, such as rate of recurrences and mitotic index, were correlated with aneuploidy of the tumour. FCM studies are, therefore, recommended to gain further parameters for the estimation of proliferative activity of pituitary adenomas.
