LOSS OF MATERIAL FROM CHROMOSOME ARM 1P DURING MALIGNANT PROGRESSION OF MENINGIOMA REVEALED BY FLUORESCENT IN-SITU HYBRIDIZATION

BACKGROUND. Atypical and anaplastic meningiomas tend to recur and to i nvade adjacent brain, bone, and skin. They also can metastasie to extr acranial organs such as the lung, liver, or bone, causing death. Recen t reports have indicated that allelic deletion of chromosome 1p is ass ociated with malignant progression of meningiomas. METHODS. Cytogeneti c analysis of 37 meningiomas was performed using double-target fluores cent in situ hybridization (FISH) and focusing on chromosome arm 1p. T he meningioma series included 17 benign meningiomas, 11 atypical menin giomas, and 9 anaplastic meningiomas. FISH was performed with pericent romeric (1q12) and subtelomeric (1p36) DNA probes to cell nuclei prepa red from surgically extirpated tumor samples. RESULTS. A high incidenc e of deletion of at least part of 1p was observed in 60.0% of atypical and 85.7% of anaplastic meningiomas. Furthermore, statistically signi ficant differences were found with respect to these data between benig n versus atypical/anaplastic meningiomas. In four cases both primary a nd recurrent tumors from the same patient also were investigated for a llelic status. CONCLUSIONS. The results of the current study support t he existence of tumor suppressor gene(s) on 1p associated with maligna nt progression of meningioma, and suggest that detection of the alleli c status of chromosome 1p by FISH may assist physicians in predicting the clinical prognosis of patients affected by this type of brain tumo r. (C) 1998 American Cancer Society.