Structure
- Complete deletion of both the short arm of chromosome 1 (1p) and the long arm of chromosome 19 (19q)
- Unbalanced whole-arm pericentromeric translocation between chromosomes 1(p;q) and 19(p;q) produces derivative chromosomes 1p19q and 1q19p, followed by the deletion of the derivative chromosome 1p19q (n.b. the translocation break point in this case is a gene-poor centromeric region hence deletion occurs, rather than preservation and the production of a fusion gene product seen in other cancers).
Clinical significance
- Pathognomic for oligodendroglioma
- Strongly associated with IDH mutation
- Has an improved survival with chemotherapy
- Mutually exclusive of ATRX & TP53 mutations
- van den Bent et al., 2006:
- Trial of radiotherapy versus chemoradiotherapy showed the radiotherapy only arm with 1p19q loss did better than the chemoradiotherapy arm without loss of 1p19q suggesting again the prognostic nature of these molecular markers
- van den Bent et al., 2013, Cairncross et al., 2013
- Survival advantage for 1p19q deleted tumours treated with radiotherapy and chemotherapy
- Suggesting that this chemoradiotherapy needs to be standard care for these tumours .
Test
- Indications for testing:
- Whenever oligodendroglial features are present or suspected.
- Procedure:
- Takes 3-7days. (Longer/more complex)
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