An improved understanding of the paracaspase MALT1 has brought clarity to the mechanisms underlying the molecular biology of MALT lymphomas.

When bcl10 expression is increased by translocation, it binds to its normal partner, MALT1 and together they increase the activity of IK kinase, resulting in the increased translocation of NF-κB into the nucleus. Alternatively, this same pathway can be activated by the novel fusion, API2-MALT1, which does not require bcl10. Therefore, both the t(1;14) resulting in deregulation of bcl10 and the t(11;18) resulting in a novel fusion API2-MALT1 appear capable of activating IK kinase, which leads to the phosphorylation and subsequent degradation of IκB and translocation of NF-κB into the nucleus. NF-κB induces the transcription of a number of different genes, including those involved in inflammation, cell viability and the immune response. Although both translocations were thought to promote lymphomagenesis by directly inhibiting apoptosis, this now seems less likely. However, this does not preclude that both translocations may affect the apoptotic signaling pathway indirectly by altering downstream apoptotic events resulting from increased nuclear NF-κB.0