TNFSF13B and Pleural effusion: In addition, an increased BAFFR expression in lung cancer may be inferred based on the report from Koizumi et al. that the expression of BAFF, the most important ligand of BAFFR, is associated in TILs with the expression of BAFFR [45] and that BAFF has remarkably higher expression in T lymphocytes from lung cancer-associated pleural effusions [46].