Prognostic implications of telomerase expression in pituitary adenomas

Objectives: To analyse the prognostic value of telomerase expression in patients with pituitary adenomas (PAs) followed-up for at least 8 years. Patients and methods: A retrospective study was conducted of samples from 51 PAs (40 typical and 11 atypical) from patients who underwent transsphenoidal surgery between 2006 and 2008 and from 10 normal pituitary glands obtained by autopsy. Telomerase expression was assessed by immunohistochemistry, correlating the expression with that of Ki-67 and p53. Results: We observed telomerase expression in 43 PAs (84.3%, 32 of the 40 typical PAs and in the 11 atypical PAs), which was higher in the clinically nonfunctioning cases (P =.0034) and very rare in the patients with acromegaly (P =.0001). There was a significant association between the percentage of tumour cells (> 10%) and the recurrence of the adenoma (P =.039). There was no correlation with the expression of Ki-67 and p53 (P =.4986), and there were no differences according to age, sex, tumour size and invasiveness. Conclusions: A telomerase expression rate greater than 10% in the pituitary tumour tissue was associated with recurrence or progression of the PA, especially in the nonfunctioning cases.