Tumor grade-related NDRG2 gene expression in primary and recurrent intracranial meningiomas

Approximately 30% of all primary CNS tumors are meningiomas. Depending on histological type, meningiomas can recur as follows: benign-with five-year recurrence of 5%, atypical-recurrence approximately 40%, and anaplastic with recurrence of 50-80%. In an attempt to understand the molecular mechanism of meningioma recurrence we investigated the N-Myc downstream-regulated gene 2 (NDRG2), which has recently been described as important in suppressing cellular carcinogenesis in different types of cancer. The objective of the study was to investigate NDRG2 gene expression at the mRNA level in primary and recurrent meningiomas as a potential marker of tumor aggressiveness, malignancy, and recurrence. Primary and recurrent meningiomas of WHO grades I, II, and III from 35 patients operated on between 2005 and 2008 year at the Department of Neurosurgery of Kaunas Medical University Hospital (Lithuania) were studied. Using the qRT-PCR method we measured NDRG2 gene expression at the mRNA level in primary (n = 24) and recurrent (n = 11) meningiomas. Statistically significant differences in NDRG2 gene expression level were observed between primary and recurrent meningioma groups (P < 0.05) and between benign (WHO grade I) and atypical (WHO grade II) meningiomas (P < 0.05). No statistically significant differences were observed (P > 0.05) among histological subtypes of benign (WHO grade I) meningiomas: fibrous, meningothelial, and transitional. In accordance with our results, reduction of NDRG2 gene expression at the mRNA level could help to explain malignant progression and predisposition to recurrence in meningiomas.