For instance, the expression of CD37L (also known as 4-1BB ligand or TNFSF9) is shown to be present in the BM of the B-cell lymphomas, including mantle cell lymphoma, follicular lymphoma, B-lymphoblastic leukemia, and lymphoplasmacytic lymphoma, but not in those with reactive lymphoid aggregates, indicating that interaction of CD137/CD137L signaling may be essential in B-cell oncogenesis and could be targeted in immunotherapies (Zhao et al., 2014). Here, TNFSF9 is linked to B-cell non-Hodgkin lymphoma.