Bone marrow neoplastic
Bone marrow - plasma cell and lymphoid neoplasms
B lymphoblastic leukemia/lymphoma with recurrent genetic abnormalities
t(12;21)(p13;q22)


Topic Completed: 1 February 2013

Minor changes: 19 June 2020

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PubMed Search: B lymphoblastic leukemia t(12;21)(p13;q22) TEL-AML1 ETV6-RUNX1

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Cite this page: Mihova D. t(12;21)(p13;q22). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/leukemiapreBALLt1221.html. Accessed November 23rd, 2020.
Definition / general
  • 20 - 30% of childhood preB ALL; most common translocation (Chin Med J (Engl) 2003;116:1298) but not infants; also 3% of adults
  • 5 different patterns of gene expression involving 14 genes, can detect with gene chip (BMC Genomics 2007;8:385)
  • Excellent prognosis due to good response to chemotherapy; 90% remissions; relapses occur later than other ALL
  • Persistence of TEL-AML1 transcripts is not necessarily related to relapse (Pediatr Int 2003;45:275)
Microscopic (histologic) description
  • No distinct morphology
Positive stains
Negative stains
Molecular / cytogenetics description
  • Fusion of TEL/ETV6 and AML1/RUNX1/CBFA2 genes
  • Detect with FISH or PCR; not found by conventional cytogenetics (i.e. are cryptic) because rearranged segments are too small
  • May have no other molecular abnormalities, almost never > 50 chromosomes
Molecular / cytogenetics images

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FISH: t(12;21)(p13;q22)
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