The purpose of this study was to elucidate the relationship between pituitary tumor transforming gene (PTTG) and invasiveness in pituitary macroadenomas and to determine the association between PTTG and both the tumor proliferative activity marker proliferation cell nuclear antigen (PCNA) and the angiogenic factor basic fibroblast growth factor. A total of 70 patients with pituitary adenomas who underwent transsphenoidal or craniotomy surgical resection were enrolled. The average age were 42.5 +/- 13.7 years (17-64 years) for the invasive group and 46.8 +/- 12.1 years (16-71 years) for the non-invasive group, with no significant difference (P = 0.179) between the two groups. RT-PCR analysis of a group of pituitary macroadenomas demonstrated that the expression levels of PTTG and PCNA in invasive pituitary adenomas were significantly higher than in non-invasive pituitary adenomas. Both factors are both closely related to the invasive growth of pituitary adenomas and may possibly serve as important markers of this growth. In conclusion, PTTG may promote invasive tumor growth by stimulating pituitary adenomas proliferation. The mechanisms of tumor growth promotion and invasion of the surrounding structures by PTTG need to be further explored.