gms | German Medical Science

Objective: Expression levels of nucleocytoplasmic shuttling receptors (karyopherins) such as karyopherin a2 (KPNA2, importin) and chromosome region maintenance protein 1 (CRM1, exportin) have been found to correlate with a higher WHO grade and a poorer prognosis in patients with infiltrative astrocytomas. The aim of this study was to evaluate these karyopherins as novel biomarkers also for meningiomas of WHO grades I-III.

Method: Nuclear expression of KPNA2, CRM1 and the MIB1 labeling index were analyzed by immunohistochemistry in 108 primary (44 meningiomas WHO grade I, 47 atypical meningiomas WHO grade II, 17 anaplastic meningiomas WHO grade III) and 13 recurrent meningiomas. Statistical analysis was performed using standard techniques.

Results: KPNA2 (p<0.001) and CRM1 (p=0.002) expression levels correlated significantly with the histological grade. KPNA2 expression correlated with proliferative activity as assessed by the MIB1 index (p<0.001). Recurrent tumors expressed significantly higher levels of KPNA2 (p=0.045) when compared to primary growths. A multivariate Cox regression analysis with sex, age, preoperative and postoperative KPS, degree of resection, histology, administration of radiotherapy, preoperative presence of neurological deficit, tumor location, tumor size as well as KPNA2 and CRM1 immunostaining and the MIB1 labeling index as covariables identified higher KPNA2 and CRM1 expression levels as independent predictors of tumor recurrence in the overall series as well as in patients with atypical meningiomas.

Conclusions: KPNA2 and CRM1 expression may have potential as novel biomarkers for meningiomas.