TNFRSF11B and breast cancer: PTX3 silencing in MDA-MB-231 cells transfected with PTX3 siRNA significantly decreased TNF-α-mediated RANKL production in the co-culture system (Figure 6B), but did not modulate OPG production (Figure 6C), supporting the notion that PTX3 may serve as an inflammatory mediator involved in breast cancer-related osteolysis.