The DNA sequence of the third-complementarity-determining region (CDRIII) of the immunoglobulin heavy chain (IgH) gene in a case of Burkitt's lymphoma was determined by polymerase chain reaction (PCR) using template DNA extracted from a smear stored at room temperature for more than one year.
To investigate the influence of breakpoint locations within the MYC gene on MYC transcript levels, we determined both the precise genomic MYC/IGH breakpoints and the amount of MYC mRNA in 25 samples of pediatric Burkitt's lymphoma with translocation t(8;14)(q24;q32).
A high Ki-67 proliferation index and positive bcl-2 staining (on cytospin slides or cell block material) of cases not conforming to typical Burkitt lymphoma morphology should prompt FISH analysis for c-MYC and/or IGH-BCL2 rearrangements to identify DHL, particularly if tissue biopsy is not expected.
The chromosomal translocation t(8;14)(q24;q32) with juxtaposition of MYC to enhancer elements in the immunoglobulin heavy chain (IGH) gene locus is the genetic hallmark of the majority of Burkitt lymphoma and a subset of Diffuse large B-cell lymphoma patients.
Thus, the capacity of Tat to spontaneously penetrate B-cells could be sufficient to favor the occurrence of MYC-IGH oncogenic rearrangements during erroneous repair, a plausible cause for the increased incidence of Burkitt lymphoma in the HIV-infected population.
Patients demonstrating a terminal deoxynucleotidyl transferase (TdT)-positive precursor B cell phenotype with IGH-MYC rearrangement have been reported to be molecularly distinct from BL and closer to B-ALL/LBL.