t(2;3)(p23;q21) TFG/ALK

2001-08-01   Jean-Loup Huret 

1.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

Clinics and Pathology


  • Anaplasic large cell lymphoma: translocations involving 2p23 are found in more than half cases of anaplasic large cell lymphoma (ALCL), a high grade non Hodgkin lymphoma (NHL). They involve ALK, and are therefore called ALK+ ALCL.
  • The most frequent ALK+ ALCL being the the t(2;5)(p23;q35) with NPM1 -ALK fusion protein, which localises both in the cytoplasm and in the nucleus.
  • The t(2;3)(p23;q21) is very rare., and, like other t(2;Var) involving various partners and ALK, the fusion protein has a cytoplasmic localization; they are therefore called "cytoplasm only" ALK+ ALCL.
  • Epidemiology

    only 2 cases to date: a 10 yr old girl and a 19 yr old man.


    ALK+ ALCL without the t(2;5) (so called cytoplasmic only ALK cases) show clinical features similar to those of classical ALK+ ALCL: young age, male predominance, presentation with advanced disease, systemic symptoms, frequent involvement of extranodal sites, and a good prognosis. Nothing in particular is known concerning t(2;3) cases.

    Genes Involved and Proteins

    Gene name
    ALK (anaplastic lymphoma receptor tyrosine kinase)
    Protein description
    1620 amino acids; 177 kDa; glycoprotein (200 kDa mature protein) ; membrane associated tyrosine kinase receptor
    Gene name
    TFG (TRK-fused gene)
    Protein description
    406 amino acids, 44 kDa; widely expressed
    Somatic mutations
    apart from the TFG-ALK herein described (see below), TFG is also known to de fused to NTRK1ID: 216> in a subset of

    Result of the Chromosomal Anomaly


    5 TFG - 3 ALK83 kDa and 96-97 kDa; as the breakpoint in TPM3 was variable , 701 amino acids in the sort er fusion protein, composed of 138 N-term amino acids from TFG, including the cioled-coil oligomerization domain fused to the 562 C-term amino acids from ALK (i.e. the entire cytoplasmic portion of ALK with the tyrosine kinase domain); homodimerization of the fusion protein.

    Expression localisation

    cytoplasmic localisation (in contrast with the t(2;5)(p23;q35) with NPM1-ALK, which localizes both in the cytoplasm and in the nucleus).


    Pubmed IDLast YearTitleAuthors
    109949992000Pathobiology of NPM-ALK and variant fusion genes in anaplastic large cell lymphoma and other lymphomas.Drexler HG et al
    105562171999TRK-fused gene (TFG) is a new partner of ALK in anaplastic large cell lymphoma producing two structurally different TFG-ALK translocations.Hernández L et al
    113803912001Alk+ CD30+ lymphomas: a distinct molecular genetic subtype of non-Hodgkin's lymphoma.Morris SW et al
    103815341999t(1;2)(q21;p23) and t(2;3)(p23;q21): two novel variant translocations of the t(2;5)(p23;q35) in anaplastic large cell lymphoma.Rosenwald A et al
    110900482000CD30(+) anaplastic large cell lymphoma: a review of its histopathologic, genetic, and clinical features.Stein H et al


    Fusion gene

    TFG/ALK TFG (3q12.2) ALK (2p23.2) M t(2;3)(p23;q12)|TFG/ALK TFG (3q12.2) ALK (2p23.2) TIC
    Atlas Image
    t(2;3)(p23;q21) G- banding - Courtesy Melanie Zenger and Claudia Haferlach.


    Jean-Loup Huret

    t(2;3)(p23;q21) TFG/ALK

    Atlas Genet Cytogenet Oncol Haematol. 2001-08-01

    Online version: http://atlasgeneticsoncology.org/haematological/1217/t(2;3)(p23;q21)

    External Links