MMP13 and cancer: In addition, the cancer cell-derived osteoclast-activating factors MCSF, IL-6, IL-8, RANKL, MMP2, MMP13, RUNX2 and PTHrP [6] are significantly down-regulated in MDA-MB-231 cells transfected with miR-124 mimic (Additional file 1: Figure S7a) and up-regulated in MCF7 cells transfected with miR-124 inhibitor (Additional file 1: Figure S7b).