Significance of Molecular Markers and Deletion of 1p/19q In Oligodendroglioma Patients by Fluorescence in Situ Hybridization Technique: An Institutional Study

Background: 1p/19q loss is caused by a non-balanced translocation t (1;19) (q10; p10), which causes one of the derived chromosomes to be lost. Since 1p/19q deletion is almost exclusively found in glial tumors with Oligodendroglial morphology up to 90% of oligodendrogliomas and up to 50% of oligoastrocytomas, with the exception of pediatric cases, where this mutation is uncommon. It is thus a particularly useful genetic marker. IDH status has major prognostic implications for patients with diffuse gliomas and was suggested to be a better predictive factor for benefit to chemotherapy in the Radiation therapy oncology group trial on adjuvant Procarbazine, Lomustine, and Vincristine (PCV) chemotherapy in anaplastic Oligodendroglial tumors. Materials and Method: In present study, formalin-fixed, paraffin-embedded (FFPE) blocks of 25 Glioma patients enrolled for study of 1p/19q codeletion. Signal pattern for FISH results is OOGG for normal & OOG for deletion. Orange signal was tagged for target and green signal tagged for control. Statistical analysis was performed by SPSS software and p valve ≤ 0.05 was considered as significant. Results: In present study, 19(76%) patients had 1p/19q co-deletion, 2(8%) normal, 4(16%) had partial deletion of 1p or 19q. Results were correlated with variables and found that 1p deletion status shows significant with IDH, 19q deletion status shows significant with tumor type & tumor grade and co-deletion of 1p/19q shows significant with tumor type, tumor grade, P53 status. Conclusion: As compare to 19q deletion, 1p is frequently shows deletion and ratio of 1p deletion is more compared to 19q deletion. These findings suggest that genetic alterations involving 1p and 19q may be important in glioma development and progression and may be associated with other molecular markers such as IDH and p53. The significance of 1p deletion with IDH status and 19q deletion with glioma type grade status may indicate potential interactions or pathways involved in glioma tumorigenesis. The significant association of 1p/19q co-deletion with type of glioma, grade of glioma, Ki67 expression, and p53 status may suggest that 1p/19q co-deletion could be a useful biomarker in predicting the behavior and prognosis of gliomas. FISH is powerful tool to analyses cytogenetic abnormality in patients with 1p/19q co-deletion.