Background:
The p16 (CDKN2A) gene is located in chromosome region 9p21. Alterations of this tumor suppressor gene have been observed in gliomas and meningiomas, as well as other cancers. Fluorescence in situ hybridization (FISH) in interphase nuclei and in metaphase spreads will detect deletions of this gene which of been associated with unfavorable prognosis.1,2 Results of this FISH assay should be considered in context of routine chromosome analysis, when possible.
Methodology:
Slides are prepared per standard protocols and 100-200 interphase cells are scored.
*Please note: it is our laboratory policy to analyze at least one metaphase cell in an interphase FISH study, if possible, including both normal and abnormal cells if both exist.
Specimen Requirements:
- Bone Marrow: Shortly before aspiration add 0.2 cc of Sodium Heparin (1,000 units/ml) to tube of transport medium (please contact lab to arrange for transport medium to be sent). Add at least 1 cc of bone marrow aspirate to the tube and suspend well. Allow no clots to form.
- Peripheral blood: May be used if bone marrow is inaspirable and blasts (.5%) are present. Send in Sodium Heparin tube.
- Bone core biopsy: May also provide cells in cases where marrow is severely packed. Send in transport medium with Sodium Heparin.
- Lymph node or tumor: Tumor specimens of at least 0.5 cm3 (up to 3 inches in diameter) are immediately collected with sterile methods into closable containers with sterile transport medium.* Needle biopsies will be accepted, but are often difficult to grow. Deliver the specimen in transport medium to the laboratory within a day, if possible, with decreased success rates as specimens are delayed in transit. Protect sample from temperature extremes during shipping.
*Sterile Ringer’s solution, either lactated or non-lactated and sterile isotonic saline are alternatives, if no complete RPMI is available. Contact Client Services for more information on media requirements.
It is preferable to collect the specimen before initiation of chemotherapy in the patient. Tumor samples should be selected from viable areas, with as little normal or necrotic material as possible.
Fluid samples (e.g., ascitic or pleural fluid) do not require culture medium for collection, but should be collected and transported aseptically.
Unacceptable specimens are acellular, necrotic specimens, septic specimens, specimens in fixative or frozen, or specimens collected more than one week previously.
- Formalin-fixed paraffin-embedded tumor block or FFPE slides: Store at room temperature. Preferred slice thickness is 5 micrometer on +charged slides. Please submit 5-10 slides. Contact Client Services for more information.
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please provide detailed clinical information.
Test Performed (Days):
Mon - Sat
Turn Around Time:
3-7 days
Shipment Sensitivity Requirements:
Ship via overnight express, using the FedEx priority overnight label provided. Contact Client Services at (855) 535-1522 for shipping kits and instructions.
References:
Additional Info:
- Korshunov A, et al: The prognostic relevance of molecular alterations in glioblastomas for patients age greater than 50 years. Cancer 104:825-832, 2005.
- Perry A, et al: A role for chromosome 9p21 deletions in the malignant progression of meningiomas and the prognosis of anaplastic meningiomas. Brain Pathol. 12:183-190, 2002.