Loss of ABCC5 in breast cancer cells results in diminished osteoclast differentiation in vitro. Mouse bone marrow cells were primed with M-CSF and RANKL for 3 days and then cultured for 2 days untreated (negative control, NC), RANKL treated (positive control, PC), or conditioned media from 4T1-derived populations (scrambled shRNA (Scr), abcc5 shRNA 1, and abcc5 shRNA 2). Osteoclasts were counted for each condition, and the results are expressed as a percentage of the osteoclast number in the positive control. The data are presented as averages of five independent experiments (*P < 0.05). Representative images are presented for each group. The scale bar in the first image represents 100 μm and applies to all images.