title: T(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas are heterogeneous with respect to the V(H) gene mutation status.
abstract: OBJECTIVE
  To investigate how t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas relate to other marginal zone lymphomas with respect to the somatic mutation pattern of the V(H) genes and the expression of the marker CD27.
  
  
  METHODS
  The V(H) gene of 7 t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas was amplified by PCR using family specific V(H) primers and a consensus J(H) primer. PCR products were sequenced and mutation analysis of the CDR and the FR regions was performed. All cases were immunostained for CD27.
  
  
  RESULTS
  One case showed unmutated V(H) genes while the others showed mutated V(H) genes with mutation frequencies ranging from 1.3 to 14.7% and with evidence of antigen selection in 2 cases. These data suggest that the translocation t(11;18)(q21;q21) can target either B-cells at different stages of differentiation or naive B-cells that retain the capacity to differentiate upon antigen stimulation. All cases but one displayed weak to strong CD27 expression which did not correlate with the V(H) gene mutation status.
  
  
  CONCLUSIONS
  t(11;18)(q21;q21)-positive gastrointestinal MALT lymphomas are heterogeneous with respect to the V(H) mutation status and CD27 is not a marker of somatically mutated B-cells.
authors.affiliation: Xavier Sagaert, Vera Vanhentenrijk, Gert De Hertogh, Karel Geboes, Thomas Tousseyn, Department of Morphology and Molecular Pathology, University Hospitals Leuven, 3000 Leuven, Belgium.
authors.forename: Xavier
authors.initials: X
authors.lastname: Sagaert
authors.forename: Brigitte
authors.initials: B
authors.lastname: Maes
authors.forename: Vera
authors.initials: V
authors.lastname: Vanhentenrijk
authors.forename: Mathijs
authors.initials: M
authors.lastname: Baens
authors.forename: Eric
authors.initials: E
authors.lastname: Van Cutsem
authors.forename: Gert De
authors.initials: GD
authors.lastname: Hertogh
authors.forename: Karel
authors.initials: K
authors.lastname: Geboes
authors.forename: Thomas
authors.initials: T
authors.lastname: Tousseyn