3 - 10 days
FISH for 1p19q Deletion in Gliomas
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Fluorescence In Situ Hybridization (FISH)
This test detects copy number changes of the short arm of chromosome 1 (1p) and the long arm of chromosome 19 (19q) using fluorescence in situ hybridization (FISH) in formalin-fixed paraffin-embedded tissue specimens. FISH is performed using two separate hybridizations, each with two FISH probes. One hybridization employs a probe specific to 1p36 along with a control 1q25 probe. The other employs a probe specific to 19q13 with a control 19p13 probe. The presence or absence of a deletion is determined by the signal ratio of each respective probe pair. 1p/19q co-deletion occurs in 44-69% of classic oligodendrogliomas and 21-33% of mixed oligoastrocytomas. This alteration is relatively infrequent in pure astrocytomas (6-8%) and can therefore be useful in the classification of gliomas. In addition, 1p/19q co-deletion is associated with more favorable prognosis and response to specific chemotherapeutic and radiotherapeutic regimens - particularly in anaplastic oligodendroglioma or oligoastrocytoma.
Interpretive report provided
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
A formalin-fixed, paraffin-embedded tissue block containing sufficient neoplastic cells is preferred. Unstained slides (3, 4-micron slides) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature.