Screening of Glioma Patients for 1p/19q Region with Fluorescent Probes

Abstract

Oligodendroglial tumors represent approximately 4-7% of all gliomas. The discovery of 1p and 19q chromosomal arms deletion in glial tumour influence the diagnosis and more accurate prediction of chemotherapy response. As a result, an attempt has been made to detect deletion using fluorescent insitu hybridization (FISH) and to determine its prognostic value in a cohort of glial tumour patients from Hyderabad population. The FISH analysis was carried out on 90 FFPE tissue sections by using Vysis LSI 1p36/LSI 1q25 and LSI 19p13/LSI 19q13 dual colored FISH probe sets. Signals were scored from 150-250 non-overlapping, intact nuclei. The analysis for 1p and 19q deletions was observed in (21/35) 60% of oligodendroglyomas which included (8/21) 38.1% of grade II and (13/21) 61.9% of grade III. Isolated 19q deletion was seen in (1/21) 4.7% & lone 1p loss was not observed in oligodendroglyomas. In mixed oligoastrocytomas combined 1p/19q loss was observed in (7/16) 43.75% cases, including one grade II and 6 grade III tumors and 1/16 (6.25%) showed isolated 1p loss & 19q deletion. This disorder was not observed in astrocytomas. The oligodendroglial phenotype was found to be significantly associated with a loss of 1p (p< 0.05), a loss of 19q (p<0.05) and a combined loss of 1p and 19q (p< 0.05). Frontal location of a tumor occurred to be a statistically significant factor unfavorable for prognosis, p<0.05. The result of our study concludes 1p/19q deletions have prognostic significance and determines deletion 1p/19q by FISH into diagnostic and treatment algorithm in gliomas.