NEUROFIBROMATOSIS TYPE 2 SEQUENCING AND DELETION/DUPLICATION ANALYSIS IN TUMOR (NF24)
Acceptable specimen types:
It is suggested to submit at least 2 anatomically distinct tumors, however a single tumor can be provided. If a blood specimen is provided with the submitted tumor, confirmatory testing in the germline will be provided at no additional charge.
Fresh tumor specimens consisting of >70% pure tumor cells. For additional, details click here.
- Frozen tumor tissue that has been snap frozed and shipped in dry ice consisting of >70% tumor cells. For additional details, click here.
- Paraffin embedded tumor tissue consisting of >70% pure tumor cells. For additional details, please click here.
- 30 working days
Candidates for this test:
- Patients with one or more features associated with NF2 without a family history of the condition and/or no mutation was identified by blood based testing.
We offer a comprehensive test using gDNA-based direct sequencing of all NF2 exons (and flanking acceptor.donor intronic sequences) and MLPA analysis to detect copy number changes. Copy number changes are confirmed by quantitative PCR or aCGH.
Using this approach, mutation detection rate in leukocytes is >90% in non-founder NF2 patients. Mutations detected include truncating mutations (nonsense, frameshift, splicing mutations), missense mutations, multi-exon deletions or duplications and total gene deletions.
In about 25-30% of founders (simplex cases, patients with unaffected parents), mutations are not detected in blood lymphocytes as a result of somatic mosaicism. Only mutations with mosaicism levels greater than 10% can be detected in lymphocyte DNA (Evans et al, 2007). Identification of the majority of mosaic mutation requires testing of tumor tissue (Evans et al, 2007). As RNA is most often degraded in available tumor material, a DNA-based comprehensive analysis is applied.
We require snap-frozen tumor tissue, a fresh tumor specimen immersed in PBS or culture medium (preferred), OR a tumor block.
In cases where surgery is scheduled, the MGL prefers that the tumor that is removed be cleaned of normal surrounding tissue, immersed in PBS or culture medium and shipped overnight to the MGL at ambient temperature.
If a tumor block is the only available material, we request that the whole tumor block be sent to us for processing. After the analysis, the tumor block will be sent back to the referring site. If the entire tumor block cannot be sent, we request that a part of the tumor is carved out from the block, avoiding the surrounding normal tissue and paraffin. To ensure that only the tumor will be excised, cut from the middle of the block where the tumor is positioned. To prevent contamination, first cut off some slices from the block using a clean knife. The minimum diameter of the tumor sample should be 0.5 cm. Place the tumor sample in a sterile container. We cannot accept samples that are not processed in this manner.
For sporadic patients with multiple schwannomas but without vestibular nerve involvement and in whom NF2 mutations are found in the tumor, we will only be able to differentiate between mosaic NF2 and schwannomatosis if material from 2 separate tumors is available and provided. There will be no additional cost associated with the analysis of more than one tumor.
SPECIMEN SHIPPING AND HANDLING:
- Please find specimen requirement specifications above.
- Specimens must be packaged to prevent breakage and absorbent material must be included in the package to absorb liquids in the event that breakage occurs. Also, the package must be shipped in double watertight containers (e.g. a specimen pouch + the shipping company’s diagnostic envelope).
- To request a sample collection kit, please click here or email firstname.lastname@example.org to complete the specimen request form.
- Please contact the MGL (via email at email@example.com, or via phone at 205-934-5562) prior to sample shipment and provide us with the date of shipment and tracking number of the package so that we can better ensure receipt of the samples.
Note: Detailed and accurate completion of this document is necessary for reporting purposes. The Medical Genomics Laboratory issues its clinical reports based on the demographic data provided by the referring institution on the lab requisition form. It is the responsibility of the referring institution to provide accurate information. If an amended report is necessary due to inaccurate or illegible documentation, additional reports will be drafted with charge.
Requests for Molecular Genetic testing will not be accepted for the following reasons:
- No label (patients full name and date of collection) on the specimens
- No referring physician’s or genetic counselor’s names and addresses
- No billing information
For more information, test requisition forms, or sample collection and mailing kits, please call: 205-934-5562.
Other related test options:
- NF2 Sequencing and Deletion/Duplication analyhsis via Blood (NF21)
- Schwannomatosis Panel Testing via Tumor (SCHP)