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1p and 19q Detection Assay by FISH

1p/19q in Glioma, 1p/19q deletion, FISH for 1p/19q

Department

Cytogenetics

Specimen Collection Criteria

Collect (preferred specimen): Formalin-fixed, paraffin-embedded block with corresponding H&E slide. Tissue should be well fixed and well processed. Tissue size should be 0.2 cm x 0.2 cm x 0.2 cm. 

Also acceptable: One H&E slide plus 4 unstained tissue sections cut at 4 µm thickness and placed on charged slides. Oven dry at 60°C for 1 hour. Unbaked or air-dried slides are acceptable. Tissue adherence cannot be guaranteed for sections placed on plain glass slides. Send all slides within 6 weeks of cutting. 

Specimen must be accompanied by a completed requisition and must contain the patient's name, date of birth, collection date, ordering physician, and source of specimen. Provide pathology report with each specimen, including type of fixative and duration of fixation (if known). 

Physician Office/Draw Specimen Preparation

Maintain paraffin-embedded tissue or slides at room temperature (20-26°C or 68-78.8°F) until transport. 

Preparation for Courier Transport

Transport: Paraffin-embedded tissue or slides at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

• Tissue in fixatives other than 10% formalin.
• Improper labeling, inadequate information.
• Decalcified specimens other than Mol decal are not acceptable.  

Inpatient Specimen Preparation

Please refer to Surgical Specimen, Routine in the Beaumont Laboratory Test Directory.

In-Lab Processing

Maintain specimens at room temperature (20-26°C or 68-78.8°F) until testing.

Storage

Specimen Stability for Testing:

Paraffin-Embedded Tissue
Room Temperature (20-26°C or 68-78.8°F): Indefinitely
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Tissue Sections on Glass Slides
Room Temperature (20-26°C or 68-78.8°F): 6 weeks
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days

Laboratory

Royal Oak Anatomic Pathology – Cytogenetics Laboratory

Performed

Monday - Friday.
Results available in 7 business days.

Reference Range

A tumor is considered positive for a 1p and/or 19q deletion if the 1p/1q or 19q/19p ratios are less than 0.8 for a diagnosis of codeletion 1p/19q, both ratios must be less than 0.8.

Test Methodology

Fluorescence in situ hybridization.

Interpretation

Hybridized sections are reviewed on a fluorescence microscope by a trained Cytogenetic Technologist. The copy number status of 1p36 and of 19q13 is determined using fluorescence microscopy. Results are reviewed by the clinical cytogeneticist who will provide an interpretive report. 

Clinical Utility

Malignant gliomas are the most common type of primary brain tumor. They have been histologically classified as astrocytomas, oligodendrogliomas, and mixed gliomas. Demonstration of combined loss of the short arm of chromosome1 (1p) and the long arm of chromosome of 19 (19q) in cases of oligodendrogliomas help identify patients with increased sensitivity to treatments. These patients also have a more favorable prognosis. 

Reference

Burger PC et al. Losses of chromosomal arms 1p and 19q in the diagnosis of oligodendroglioma: a study of paraffin-embedded sections. Mod Pathol 2001:14(9): 842-853. 

Louis, D.N. et al.  WHO Classification of Tumors of the Central Nervous System, Revised 4th edition, 2016.  International Agency for Research on Cancer (IARC) Lyon Cedex 08, France. Pp. 60-74.

CPT Codes

88271x4, 88275x1.

Contacts

Last Updated

12/30/2022