The relation of pituitary adenomas invasiveness and the proliferative index measured by immunoexpression of topoisomerase IIα.

INTRODUCTION: Cavernous sinus invasion by pituitary adenoma affects surgical procedure radicality, and consequently the postoperative course and prognosis in pituitary adenomas treatment. The search for pituitary adenoma aggressive behaviour markers is still a matter of debate.

MATERIAL AND METHODS: This study evaluates the relation of pituitary adenoma invasiveness to the expression of topoisomerase IIα in 72 patients who underwent transsphenoidal pituitary surgery. The assessment of tumour growth was conducted according to the Hardy scale as modified by Wilson and the Knosp scale. Topoisomerase IIα expression in tumours specimens was evaluated using immunohistochemical staining.

RESULTS: There was a correlation between the Knosp scale degree and the topoisomerase IIα expression (Spearman R=0.3611, p<0.005). The Kruskal-Wallis H test (p=0.0034) showed that there was a statistically significant topoisomerase IIα expression increase in tumours classified as grade E on the Hardy scale. The topoisomerase IIα expression correlated also with tumour size (Spearman R=0.4117, p<0.001). Higher levels of expression were observed in macroadenomas, as compared to microadenomas (p<0.05, Mann-Whitney test). Topoisomerase IIα expression correlated with cavernous sinus invasion.

CONCLUSIONS: The topoisomerase IIα expression correlated more with invasiveness than with extensiveness, which might make it an eminently useful marker in the assessment of aggressive pituitary adenoma behaviour.