The preoperative diagnosis of cavernous sinus invasion remains difficult and 
controversial, and there are currently no reliable histological or molecular 
markers that predict pituitary tumour behaviour and response to treatment. We 
evaluated 45 patients with pituitary adenoma. The results have shown that the 
sensitivity of MRI for indicating cavernous sinus invasion in this prospective 
study was 60%, specificity 85%, positive predictive value 83.33%, negative 
predictive value 62.96%. Forty-five specimens of pituitary adenomas were 
analyzed for expression of F8, VEGF, Ki-67, c-myc, bcl-2, nm23 and MMP-9 
immunoreactivity using immunoperoxidase staining. MVD was assessed using 
F8-related antigen. The results have shown that MVD of invasive pituitary 
adenomas was significantly higher than that of noninvasive (P < 0.001). There 
was an association between the invasion of pituitary adenomas and Ki-67 LI (P = 
0.039) or the expression of VEGF (P < 0.001) and MMP-9 (P < 0.001). But c-myc LI 
and bcl-2 expression have no association with invasiveness of pituitary adenomas 
(P = 0.061 vs. P = 0.201). On the other hand, there is an inverse relationship 
between nm23 expression and tumor invasion (P < 0.001). In conclusion, 
parasellar extension of pituitary adenomas through the medial wall of the 
cavernous sinus diagnosed at surgery, can be determined by radiology with 
sensitive gadolinium-enhanced MRI. Although our study has shown that MVD and the 
expression of VEGF, Ki-67, nm23 and MMP-9 have associations with invasiveness of 
pituitary adenomas, they are lack of specificity. These markers can only provide 
some useful informations on the therapeutic strategy of pituitary adenomas.