Analysis of CDKN2A gene alterations in recurrent and non-recurrent meningioma.

Abstract

Assessment of the risk of recurrence is essential to determine the therapeutic strategy of meningioma treatment. Many relapsing or aggressive meningiomas show elevated mitotic and/or Ki67 indices, reflecting cell cycle deregulation. As CDKN2A is a key tumor suppressor gene involved in cell cycle control, we investigated whether CDKN2A alterations may be involved in tumor recurrence. We carried out a comparative analysis of 17 recurrent and 13 non-recurrent meningiomas. CDKN2Asingle nucleotide variations (SNVs), deletions, methylation status of the promotor, and p16 expression were investigated. Results were correlated with the recurrent or non-recurrent status and clinicopathological data. We identified a CDKN2A SNV (NM_000077, exon2, c.G442A, p.Ala148Thr) in five meningiomas that was significantly associated with recurrence (p = 0.03). This mutation, confirmed by Sanger sequencing and referenced in the COSMIC database in various cancers, has not been reported in meningioma. The presence of one of the three following CDKN2A alterations-p.(Ala148Thr) mutation, whole homozygous or heterozygous gene loss, or promotor methylation > 8%-was observed in 13 of the 17 relapsing meningiomas and was strongly associated with recurrence (p < 0.0001) and a Ki67 labeling index > 7% (p = 0.004). We report an undescribed p.(Ala148Thr) CDKN2A mutation in meningioma that was only present in relapsing tumors. In our series, CDKN2A gene alterations were only found in recurrent meningiomas. However, our results need to be evaluated on a larger series to ensure that these CDKN2A alterations can be used as biomarkers of recurrence in meningioma.