Absence of somatic hypermutation in the open reading frame of the bcl-2 gene participating in the t(14;18) chromosomal translocation in follicular lymphoma.

The information concerning potential effects of somatic hypermutation on bcl-2 sequences translocated to the immunoglobulin heavy chain gene (IgH) locus in follicular lymphoma (FL) is rather limited. We analysed the complete open reading frame (ORF) of the bcl-2 gene for the presence of mutations in 24 bcl-2/IgH-positive diagnostic FL samples by the single strand conformation polymorphism (SSCP) technique. A prior analysis on many of these FL samples had revealed a consistent pattern of somatic hypermutation in IgH genes. Abnormally migrating bands on SSCP gels were identified only in 4/24 samples. This result provides strong support for the notion that in FL the translocated bcl-2 coding region is not targeted by somatic hypermutation.