RANK expression was instead significantly upregulated in BMSCs after co-culture with tumor cells (Figure 1C, p < 0.01 as compared to BMSCs before co-culture), differently from MRC-5, which showed no expression of RANK before or after co-culture (data not shown), confirming a specific activation of the RANKL/OPG/RANK pathway caused by the crosstalk between tumor cells and bone microenvironment. The gene discussed is TNFRSF11A; the disease is neoplasm.