Background: Lymphomagenesis is believed to depend on clonal proliferation of neoplastic progenitor cells. For follicular lymphoma, the neoplastic progenitors are likely derived from the early B-cells, but their exact nature remains elusive. We report a case of transmission of a follicular lymphoma by allogeneic bone marrow transplantation. Follicular lymphoma developed in the donor, and subsequently in the recipient, years after the BMT. Testing supports a common progenitor cell for both the malignancies.

Methods: Sequencing of the amplifiable translocation (14;18) BCL2/IgH fusion gene product and microsatellite analysis using a commercially available human identity testing kit were used to establish the biological relatedness of the donor and recipient lymphomas. The monoclonal IgH gene rearrangements from these two lymphomas were further examined for their somatic hypermutational status.

Results: Microsatellite analysis confirmed the recipient’s lymphoma was donor cell-derived. Analysis of the monoclonal IgH gene rearrangements revealed post-germinal center cell phenotype in both tumors. The VH regions utilized were different in the donor and recipient lymphoma, demonstrating two distinct clonal populations. Despite this difference, the sequences of the translocation (14;18) fusion gene products (BCL2/IgH) from the two lymphomas were identical confirming a common progenitor cell for both malignancies.

Conclusion: Our findings strongly suggest the same neoplastic progenitor cells are responsible for the lymphomagenesis in both the donor and recipient. These findings support the concept of a lymphoma progenitor cell.

Disclosure: No relevant conflicts of interest to declare.

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