TNFSF11 and neoplasm: To investigate whether the inhibitory effect by tumor exosomes on osteoclast formation was a result of induction of apoptosis, we analyzed the mRNA expression levels of both the anti-apoptotic marker B-cell lymphoma 2 (Bcl-2) and the apoptotic activator protein Bcl-2-associated X protein (Bax) in RANKL-induced RAW264.7 cells cultured in the absence or presence of TRAMP-C1-derived exosomes.