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Juvenile Myelomonocytic Leukemia Associated Exon Panel

Item Value
Available Stat? No
Utilization Guidelines Tests with long turn-around times (i.e., Molecular based tests and Microarrays) should only be requested on an inpatient if the result is going to affect the inpatient management. If the patient will likely be discharged before the result will be available, the test should be requested after discharge. (NOTE: UCSF Medical Center is not reimbursed for inpatient testing).

An exception to the above may be appropriate if there is a possibility the patient will not survive to be discharged and the information is important for diagnosis and/or family decisions/management (e.g., recurrence risk).
Test code JMML
Performed by Medical Genomics - Molecular Diagnostics
In House Availability Run 1st and 3rd Monday of every month, day shift only
Method Next Generation Sequencing
Collection Instructions Avoid hemolysis. Due to stability issues these samples should only be collected at UCSF Monday through noon Friday.

Do not collect sample in heparin. Keep sample refrigerated for overnight or longer storage.

For UCSF Samples (from remote sites) Click here for sample collection instructions

For NON-UCSF Samples Click here for Requisition form & Account set-up instructions. Note we only do institutional billing.
Container type
Lavender top (EDTA) Blood or bone marrow
T25 flask Germiline sample
Amount to Collect
Tumor sample 5 mL blood or 3 mL Bone marrow
Paraffin embeded 10 micron FFPE sections on unstained, uncharged glass slides with one H&E stained section

Germline sample Cultured fibroblasts (confluent T25 flasks x2)
Sample type EDTA whole blood
Bone marrow aspirate
FFPE sections
Cultured fibroblasts (germline sample)
Preferred volume Tumor sample:
EDTA whole blood 5 mL
Bone Marrow aspirate 3 mL
FFPE 10 micron sections on unstained, uncharged glass slides with one H&E stained section

Germline sample:
Cultured fibroblasts Confluent T25 flasks x2
Min. Volume Tumor sample:
EDTA whole blood 2 mL
Bone Marrow aspirate 3 mL
FFPE 10 micron sections on unstained, uncharged glass slides with one H&E stained section

Germline sample:
Cultured fibroblasts Confluent T25 flasks x2
Processing notes Do not freeze blood or bone marrow samples. Ship to CB as soon as possible.
Normal range Negative
Synonyms JMML Panel; CBL exons 8/9; KRAS exons 2/3; NRAS exons 2/3; PTPN11 exons 3/4/13
Turn around times 2-4 weeks
Additional information An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.

This sequencing panel sequences the following gen es: CBL exons 8 & 9; KRAS exons 2 & 3; NRAS exons 2 & 3; PTPN11 exons 3, 4 & 13

Juvenile myelomonocytic leukemia (JMML) is a rare and aggressive, clonal myeloproliferative neoplasm (MPN) of young children characterized by over-production of myeloid lineage cells that infiltrate hematopoietic and non-hematopoietic tissues (reviewed in Loh ML. Br J Haematol 2011;152: 677-87). The diagnosis of JMML is facilitated by uncovering an underlying mutation. While the most common genetic abnormalities associated with JMML are activating mutations in CBL, KRAS, NRAS, or PTPN11, 10-15% of patients have clinical neurofibromatosis with loss of heterozygosity of the wildtype NF1 allele in their affected bone marrow, and another 10% of patients have no known mutation.

For diagnostic purposes, the sensitivity of detecting a point mutation is 15% relative to that of the normal DNA sequence. A negative result by this assay does not exclude the presence of a mutation below its 15% sensitivity level, or in genes or exons not interrogated by this assay.

This assay is intended for diagnostic genotyping of patients who are suspected of having JMML. This test is not intended to detect minimal residual disease.

This test was developed and its performance characteristics determined by the UCSF Clinical Laboratories. It has not been cleared or approved by the Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. This test is used for clinical purposes. It should not be regarded as investigational or for research. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88) as qualified to perform high complexity clinical laboratory testing.

Library preparation
PCR targeting CBL exons 8 and 9, KRAS exons 2 and 3, NRAS exons 2 and 3, and PTPN11 exons 3, 4 and 13. Following amplicon preparation of the targeted exons, standard 454Jr emulsion PCR and sequencing chemistry is used for sequence ascertainment
CPT coding 81403, 81275, 81404, 81479
LDT or Mod FDA? Yes
Last Updated 4/23/2014 2:13:19 PM
Entry Number 1474
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