Mutation-based circulating tumor DNA detection approach to monitoring the therapy response in breast cancer

Breast cancer is responsible for the highest number of cancer-related mortalities in females.1 For breast cancer patients who need systematic chemotherapy,especially with locally-advanced breast cancer,neoadjuvant chemotherapy(NAC)is pivotal in optimizing subsequent treatment strategies and is essential for enhancing overall survival rates.2 Thus,monitoring NAC response is crucial to identify the patients achieving a pathologic complete response(pCR)and the non-responders early to de-escalate or change therapy,respectively.However,current monitoring methods,such as imaging technologies(e.g.,ultrasound and magnetic resonance imaging[MRI]),traditional serum biomarkers(e.g.,CA15-3 and CEA),and core-needle biopsy with Ki67 assay during the NAC,cannot meet the need to measure the dynamic response in NAC accurately.