ADAMTS9 and breast cancer: Previous researches have reported that down‐regulation of ADAMTS9‐AS2 was in glioma,23 colorectal cancer,25 ovarian cancer26 and clear cell renal cell carcinoma.27 In addition, other reports revealed that ADAMTS9‐AS2 inhibited the tumour progression by the miR‐223‐3p/TGFBR3 axis in lung cancer.28 Shi et al also found that ADAMTS9‐AS2 is lowly expressed in breast cancer tissues and drug‐resistant breast cancer cells.