Expression of MALT1 oncogene in mouse hematopoietic stem/progenitor cells recapitulates the pathogenesis of human MALT lymphoma

Comparison of gene expression profiling analysis of bone marrow isolated CD34+ cells from patients with MALT lymphoma vs. healthy individuals revealed a large number of differentially expressed genes that included NF-kB target genes, genes involved in inflamatory signalling and immunoglobulin genes, suggesting an early lymphoid B-cell priming. Chromosomal translocations involving MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. However, targeting these translocations to mouse B-cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1+Lin- hematopoietic stem/progenitor cells (HS/PCs), leading to the development of tumors recapitulating the clinical, histopathological and molecular features of human MALT lymphomas. Ablation of the p53 gene induced transformation of MALT lymphoma to diffuse large-cell lymphoma of activated B-cell type (ABC-DLBCL). Human CD34+ cells isolated from MALT lymphoma patients displayed an abnormal transcriptional program that was shared by MALT lymphoma cells, transgenic mouse Sca1+Lin- cells and Sca1-MALT1-induced lymphomas. Our study shows that MALT lymphoma can be modeled in mice by targeting MALT1 oncogene to HS/PCs. 10 samples were analyzed of which 5 are CD34+ cells sorted from the bone marrow of MALT patients and are compared to the other 5 CD34+ cells sorted from the bone marrow of healthy donors.