Angiogenesis in pituitary adenomas - relationship to endocrine function, treatment and outcome

Angiogenesis has been shown to be related to tumour behaviour, prognosis an d response to treatment in many different tumour types. The aim of this stu dy was to examine the relationship between angiogenesis and tumour behaviou r and response to treatment in pituitary adenomas. The microvessel density (MVD) of pituitary rumours was assessed by counting blood vessels labelled with 3 different endothelial markers using antibodies to CD31, factor eight -related antigen and biotinylated Ulex europaeus (agglutinin I UEAI), One h undred and forty-two surgically removed pituitary adenomas (46 GH secreting , 6 microprolactinomas, 19 macroprolactinomas, 18 ACTH secreting and 53 fun ctionless tumours) were carefully characterized and assessed. There was a s ignificant negative correlation between age and MVD of GH secreting rumours (R-2=33.8, P=0.005). Age was not related to MVD in other tumour types. Pre -treatment hormone production by the adenomas was related to MVD in prolact inomas (P<0.05), but not in GH secreting rumours. Invasive prolactinomas we re significantly more vascular than non-invasive tumours (P<0.05). Drug tre atment with metyrapone or bromocriptine did not appear to influence tumour angiogenesis. Surgical cure was more Likely in macroprolactinomas and in AC TH secreting tumours with lower MVD. These results show that factors relate d to angiogenesis are very important in determining a number of clinical fe atures of pituitary tumours, in particular the invasiveness of macroprolact inomas, the particular the invasiveness of macroprolactinomas, the effect o f age in tumours secreting GH and the outcome of surgical treatment in macr oprolactinomas and ACTH secreting tumours.