ADAMTS9 and breast carcinoma: In cells transfected with ADAMTS9, colony formation was significantly reduced, compared to control cells (reduced to 18% of control in BT549, P < 0.01, and 40% of control in SK‐BR‐3, P < 0.001, Fig. 3D), suggesting an inhibitory effect of ADAMTS9 on proliferation in breast cancer cells.