P13.09.B MOLECULAR CYTOGENETIC ANALYSIS OF CHROMOSOME 17 AND EXPRESSION OF MIR-22, MIR-657 AND MIR-4737 REGARDING AGGRESSIVENESS AND RECURRENCE IN MENINGIOMAS OF DIFFERENT WHO-GRADES

Abstract BACKGROUND The investigation of aberrations of 17p and 17q in meningiomas is of clinical interest, as various tumor suppressor genes such as TP53 (17p13) or the serine/threonine kinases RPSK6KB1 (17q23) are encoded here. In addition, previous studies have shown that loss of 17q22 in recurrent meningiomas has prognostic value for the risk of recurrence. Concerning miR-expression, this study focuses on the expression of miR-22, miR-657 and miR-4737 in meningioma tumor tissues and blood samples of the patients. MATERIAL AND METHODS Between August 2023 and October 2024, tumor samples from 37 patients who underwent surgical treatment were collected, including 31 primary and 10 recurrent meningiomas. Patients’ blood was taken preoperatively. Using fluorescence in situ hybridization (FISH), the tumor samples were analyzed for numerical aberrations of 17p13 and 17q22. Real-time PCR was performed to measure the miR-expression in blood and tumor tissues. To evaluate the blood miR-expression, 20 healthy volunteers were included to this study. RESULTS However, losses of 17p13 and 17q22 were rare in the investigated meningiomas of all WHO-grades (average: 3.7%, range: 0%-15%), regarding the losses of 17p13 and the radiologically measured tumor volume, a significant correlation was found (r=0.477; p=0.002) and described by linear regression: 14.092 + 3.51*x (p=0.006). Apart of the losses, chromosomal gains were also detected (average: 8.8%, range: 0%-75%). The miR-expression showed that of the three candidates, only miR-22 correlated strongly negative with the WHO-grades (r=-0.669; p= <0.001). The interpaired comparison of miR-22 within WHO-grades I and III differed highly significant (p= <0.001). When comparing miR-22 expression levels in primary and recurrent meningiomas, significant lower expression was found in the recurrent meningioma group (p= 0.042). Regarding miR-blood- levels, the expression of all three candidates differed significantly from those of healthy individuals (miR-22: p=<0.001; miR-657: p=0.012; miR-4737: p=0.047). CONCLUSION Gains and losses of chromosome 17p13 and 17q22 were rarely detected in the meningiomas investigated, confirming the literature. However, chromosomal abnormalities were not only observed in high-grade tumors, as often described in the literature, but also as sporadic aberrations in benign meningiomas. With regard to miR-expressions, only miR-22 correlated significantly negatively with WHO-grades. The different expression in meningiomas of different WHO-grades indicates the influence of miR-22 in the tumor metabolism of meningiomas and could be a potential marker for high-grade meningiomas. The expression of miRNAs in patients` blood samples show evidence as potential biomarkers in liquid biopsy.