XL 4q12 DC

Translocation/Deletion Probe

Order Number
Package Size
100 µl


XL 4q12 DC

The XL 4q12 DC probe is a dual color probe which detects rearrangements and deletions at 4q12. The probe contains an orange probe hybridizing to the CHIC2 gene region. A green probe hybridizes proximal to FIP1L1, and another green probe hybridizes to PDGFRA and the region distal to the gene.

Clinical Details

The updated (2016) World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues indicates the category myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, FGFR1, or with PCM1-JAK2. Eosinophilia is a condition in which the number of eosinophilic granulocytes in peripheral blood or tissue is increased above the normal level. The hypereosinophilic syndrome (HES) is a rare hematologic disorder, characterized by a marked and persistent increase of eosinophilic granulocytes in blood or tissue accompanied by organ damage. HES is associated with neoplastic (primary) or reactive (secondary) processes. Patients suffering from hematologic disorders with eosinophilia are typically diagnosed with chronic eosinophilic leukemia (CEL), myeloproliferative neoplasms (MPN), certain variants of acute myeloid leukemia, systemic mastocytosis and others. The most frequent aberration detected in CEL (10-20%) is the interstitial deletion of the CHIC2 gene with breakpoints in the FIP1L1 and PDGFRA genes. The deletion of a fragment of about 800kb is resulting in the FIP1L1-PDGFRA fusion gene, a constitutively activated tyrosine kinase transforming hematopoietic cells. PDGFRA and PDGFRB fusions are sensitive to Imatinib, a proven treatment for BCR-ABL–positive chronic myeloid leukemia, whereas FGFR1 mutations are resistant.

Clinical Applications

  • Chronic Myelogenous Leukemia and Myeloproliferative Neoplasms (CML/MPN)


XL 4q12 DC

XL 4q12 DC hybridized to lymphocytes. Two normal interphases and one metaphase are shown.

Expected Patterns

Expected Pattern 1

Normal Cell:
Two green-orange colocalization/fusion signals (2GO).

Expected Pattern 2

Aberrant Cell (typical results):
One green-orange (1GO) colocalization/fusion signal and one green (1G) signal resulting from the loss of one orange signal.

Expected Pattern 3

Aberrant Cell (typical results):
One green (1G) and two green-orange colocalization/fusion (2GO) signals resulting from a translocation between the green labeled PDGFRA gene region and an unknown chromosome.


  • Cools et al (2003) N Engl J Med 348:1201-1214
  • Pardanani et al (2003) Blood 102:3093-3096
  • Valent et al (2012) Expert Rev Hematol 5:157-176


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