FISHing for 1p19q codel in oligodendroglioma
- Author:
Kong Po-Lian
1
Author Information
1. Genomic Medical Science@UM, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
- Collective Name:Phaik-Leng Cheah; Kein-Seong Mun; Seow-Fan Chiew; Tze-Pheng Lau; Cing-Chai Koh; Kean-Hooi Teoh; Abdul Rahman Nazarina; Lai-Meng Looi
- Publication Type:Journal Article
- Keywords:
1p19q co-deletion;
oligodendroglioma;
fluorescence in situ hybridisation;
reference range;
cut-off
- From:The Malaysian Journal of Pathology
2020;42(3):369-376
- CountryMalaysia
- Language:English
-
Abstract:
Together with isocitrate dehydrogenase (IDH) mutation, co-deletion of 1p19q (1p19q codel) is a prerequisite for diagnosis of oligodendroglioma, making it imperative that histopathology laboratories
introduce testing for 1p19q codel. To date there is still no consensus reference range and cut-offs
that confirm deletion of 1p or 19q. We embarked on determining our reference range in 11 formalinfixed, paraffin-embedded non-neoplastic brain tissue using fluorescence in situ hybridisation (FISH)
with the Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular Inc., USA). At
same time we attempted to validate our methodology in 13 histologically-confirmed IDH-mutant
oligodendrogliomas. For 1p, percentage cells with deletion (range=8-23%; mean±SD = 15.73±5.50%)
and target: control (1p36:1q25) ratio (range = 0.89-0.96; mean±SD = 0.92±0.03) in non-neoplastic
brain, differed significantly (p<0.000) from oligodendroglioma (percentage cells with deletion:
range = 49-100%; mean±SD = 82.46±15.21%; target:control ratio range:0.50-0.76; mean±SD =
0.59±0.08). For 19q, percentage cells with deletion (range = 7-20%; mean±SD = 12.00±3.49%)
and target:control (19q13/19p13) ratio (range:0.90-0.97; mean±SD = 0.94±0.02) in non-neoplastic
brain also differed significantly from oligodendroglioma (percentage cells with deletion: range =
45-100%; mean±SD = 82.62±18.13%; target:control ratio range:0.50-0.78; mean±SD = 0.59±0.09).
Using recommended calculation method, for diagnosis of 1p deletion, percentage of cells showing
deletion should be >32-33% and/or target:control ratio <0.83. For 19q, percentage of cells showing
deletion should be >22% and target:control ratio <0.88. Using these cut-offs all 13 oligodendroglioma
demonstrated 1p19q codel.
- Full text:5.2020my01083.pdf
