TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: 512F    
PDGFRB/TEL Translocation (5;12) for Chronic Myelomonocytic Leukemia (CMML), FISH

Useful For Suggests clinical disorders or settings where the test may be helpful

Identifying patients with chronic myelomonocytic leukemia and other hematologic disorders who may be responsive to imatinib mesylate

 

Identifying and tracking chromosome abnormalities and response to therapy

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results. Additional charges will be incurred for application of all reflex probes performed. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Platelet-derived growth factor receptor-beta (PDGFRB) produces a tyrosine kinase involved in cell proliferation. Translocation-ets-leukemia protein (encoded by the gene ETV6) is a gene transcription protein that is frequently rearranged in leukemias. A 5;12 translocation, t(5;12)(q33;p13), results in a fusion product (PDGFRB/ETV6) that is seen in approximately 1% to 2% of patients diagnosed with chronic myelomonocytic leukemia. Patients with this translocation often have associated hypereosinophilia.

 

Imatinib mesylate is an inhibitor of tyrosine kinases, including PDGFRB. Patients with the 5;12 translocation are reportedly responsive to imatinib mesylate; upon treatment, they usually go into complete remission.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff.

 

The presence of a positive clone supports a diagnosis of malignancy.

 

The absence of an abnormal clone does not rule out the presence of neoplastic disorder.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is not approved by the U.S. Food and Drug Administration and it is best used as an adjunct to existing clinical and pathologic information.

Supportive Data

A blinded study using the PDGFRB/ETV6 dual-color, dual-fusion (D-FISH) strategy probe was performed on 12 samples from patients identified with a t(5;12) by chromosome analysis and a series of normal control specimens. Translocation of PDGFRB and ETV6 was identified in the neoplastic specimens but was not detected in any of the control specimens. The normal controls were used to generate a normal cutoff for this assay.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Pardanani A, Reeder T, Porrata LF, et al: Imatinib therapy for hypereosinophilic syndrome and other eosinophilic disorders. Blood 2003;101:3391-3397

2. Cain JA, Grisolano JL, Laird AD, et al: Complete remission of TEL-PDGFRB-induced myeloproliferative disease in mice by receptor tyrosine kinase inhibitor SU11657. Blood 2004;104:561-564