In previous studies, it has been reported that 10-20% of acute myeloid leukemia (AML) cases showed immunoglobulin heavy chain gene (IGH) rearrangements, a genetic hallmark of B-cell differentiation. However, the clinical significance of this is uncertain. Here, we report a case of diffuse large B-cell lymphoma (DLBCL) after complete remission (CR) from AML that exhibited an IGH rearrangement.
The patient was diagnosed with AML (M4Eo) with inversion of chromosome 16 [inv(16)]. Interestingly, the AML cells showed a monoallelic IGH rearrangement, as detected by the Southern blot analysis. The rearranged band was cloned using the inverse polymerase chain reaction (PCR) method. The sequence result revealed that a recombination between DH7-27 and JH4 occurred in the AML cells. PCR using DH7-27- and JH4-specific primers yielded no band from DLBCL specimens, suggesting that the DLBCL did not occur owing to the AML cell with IGH rearrangement. In addition, fluorescent in situ hybridization (FISH) showed that inv(16) was not found in the DLBCL cells. Therefore, although the AML cells harbored an IGH rearrangement, the origins of the two tumors seemed to differ from each other.
As the prognosis of AML became better, long-term follow-up studies of AML patients might define the clinical significance of IGH rearrangements in AML cells.