Article
The genetic progression score (GPS) in meningiomas by FISH as an impartial marker for tumor recurrence
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Published: | September 16, 2010 |
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Objective: Meningiomas are tumors that arise from the coverings of the brain or the spinal cord. They are mostly benign and can often be surgically cured. However, in about 8% of the cases, an increased risk of tumor recurrence and a more aggressive clinical behavior is observed. Cytogenetically, meningiomas are well characterized with either a normal karyotype or monosomy of chromosome 22 in most of the tumors. Clinically relevant are the most common losses of the autosomes 1p, 9p, 14 and 18. The order of accumulating genetic aberrations has previously been estimated with oncogenetic tree models, and a genetic progression score (GPS) derived from these models was shown to be more predictive for tumor recurrence than the WHO classification.
Methods: 50 meningioma patients were operated by open surgery between 2008 and 2010. Tissue specimens from tumors were obtained after surgery and prepared for FISH analysis. In accordance with our previous results, we used two color FISH for chromosomal alterations of chromosome 1, 9, 14, 18 and 22.
Results: In our cohort 52% (26/50) correspond to WHO I, 40% (20/54) to WHO II and 8% (4/50) to WHO III meningiomas. The average age of all patients was 59,6 years (±11,4). It was 58,5 years (±11,4) for the female patients (32/50) and 63,4 years (±15,1) for the male patients (18/50). FISH analyses were performed in these 50 cases and for each meningioma up to 200 nuclei were evaluated. In 32 tumors we found deletions of chromosome 22. In 22 cases the deletion of the short arm of chromosome 1 was detectable. Losses of chromosome 14 were found in 13 cases, of chromosome 18 in 6 cases and of 9p in 4 cases. Based of these results, 27 cases correspond to a GPS ≤1, 6 cases to a GPS ≥1 and <6,02 and 17 cases ≥6,02 indicating a higher risk of tumor recurrence.
Conclusions: Grading and prognostic assessment of meningiomas can be controversial. Obviously the biological behavior of meningiomas can not be reflected in histological parameters alone. Cytogenetic characterization of meningiomas by FISH analysis or by karyotyping can provide an insight into their potential of recurrence by GPS classification and are therefore a valuable criterion for the neurosurgeon's postoperative management protocol.