Expression of cFLIP is necessary for diffuse large B cell lymphoma pathogenesis

Apoptosis evasion is a major feature of DLBCL. However, while the suppression of intrinsic apoptosis has long been recognized as a lymphoma-promoting event, the role of extrinsic apoptosis has remained poorly defined.

Here, we demonstrated at the genetic level that expression of cFLIP, the most crucial, non-redundant inhibitor of extrinsic apoptosis, in B cells is necessary for the development of diffuse large B cell lymphoma (DLBCL) in an autochthonous murine model. Indeed, B cell-specific deletion of Cflar, the gene encoding for cFLIP, prevented lymphomagenesis mediated by oncogenic Myd88 and overexpression of BCL2. In human lymphoma cells, we showed that the absence of cFLIP sensitizes ABC- but not GCB DLBCL subtype cells to TRAIL- or LPS-induced, Caspase-8-mediated apoptosis.