Loss of 1p in recurrent meningiomas. a comparative study in successive recurrences by cytogenetics and fluorescence in situ hybridization.

Deletion of 1p is associated with histological progression to meningiomas. Detection of this alteration may be a predicting factor for recurrences in this tumor. We present 8 meningiomas from four patients: the original tumor and the first recurrence in one patient, and the first and second recurrences in the other three were studied. We compared results of monosomy 22 and deletion of chromosome 1p with cytogenetic methods and fluorescence in situ hybridization (FISH) analysis obtained from slides of direct preparations, of cultured cells and slides of touch preparations. The cytogenetic study showed normal chromosome 22 and deletion on 1p32 in both samples of one patient; only monosomy 22 in both recurrences in another patient, and normal karyotypes with different non-clonal anomalies in the other tumors. However, with FISH analysis, monosomy 22 in both recurrences of three patients was demonstrated, as well as the loss of 1p in all tumors. These results were more evident in the analysis of direct and touch preparations than in those of cultured cells.