All patients underwent radical mastectomy with neoadjuvant chemotherapy after three courses of CMF (cyclophosphamide 600 mg/m2 d1, d8, methotrexate 0.4 mg/kg d1, fluorouracil [5‐Fu] 12 mg/kg d1‐d5, 21 days as a cycle)....High CCAT2 expression was detected in BC tissues and BC drug‐resistant cells after neoadjuvant chemotherapy, and a negative link was revealed between CCAT2 expression and efficacy of neoadjuvant chemotherapy.