乳腺癌是全球妇女最常见的恶性肿瘤。液体活检是从血液和体液中获取肿瘤衍生物的方法。这包括循环肿瘤细胞（CTCs）、循环肿瘤脱氧核糖核酸（ctDNA）、肿瘤教育血小板（TEPs）和外泌体的评估。液体活检检测CTCs和ctDNA已被证明在早期和转移性乳腺癌中具有预后和预测价值。研究CTCs还可以推进我们对肿瘤生物学的了解，包括上皮间质转化。ctDNA可用于评估和监测乳腺癌的分子特征。它可以帮助在临床特征或放射学证据出现之前检测肿瘤中的新遗传变异并预测疾病进展。TEPs和外泌体也正在成为乳腺癌的诊断、预后和预测标志物。因此，液体活检提供了一种非侵入性、可重复评估肿瘤动态的方法。已经使用许多方法检测CTCs和ctDNA。其中大多数仍处于研究阶段，只有CellSearch方法用于CTCs的检测和Therascreen PIK3CA RGQ聚合酶链反应（PCR）用于液体活检中PIK3CA（磷酸二酯酰甘油酸-4,5-二磷酸3-激酶催化亚基α）突变的检测已经获得了美国食品和药物管理局的批准。然而，其高成本、缺乏标准化操作程序以及长且复杂的检测过程限制了它们的使用。尽管存在限制，液体活检在临床决策中是一种有用的工具，并有潜力在未来在乳腺癌管理中发挥日益重要的作用，因为我们朝着更个性化的癌症护理前进。

Breast carcinoma is the most common malignancy among women worldwide. Liquid biopsy is a method of obtaining tumour-derived material from blood and body fluid. This includes the assessment of circulating tumour cells (CTCs), circulating tumour deoxyribose nucleic acid (ctDNA), tumour educated platelets (TEPs) and exosomes. Detection of CTCs and ctDNA in liquid biopsy has been shown to have prognostic and predictive value in both early and metastatic breast carcinoma. The study of CTCs could also advance our understanding of aspects of tumour biology, including epithelial mesenchymal transition. ctDNA can be used to assess and monitor the molecular profile of breast carcinoma. It may help detect new genetic alterations in tumours and predict disease progression before the onset of clinical features or radiological evidence. TEPs and exosomes are also emerging as diagnostic, prognostic and predictive markers of breast carcinoma. Thus, liquid biopsy provides a non-invasive, repeatable method for the dynamic assessment of the tumour. Many methods have been used for the detection of CTCs and ctDNA. Most of these are still in the research stage and only the CellSearch method for the detection of CTCs and Therascreen PIK3CA RGQ polymerase chain reaction (PCR) assay for the detection of PIK3CA (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha) mutations in liquid biopsy have approval of the United States, Food and Drug Administration. However, their high costs, lack of standardized procedures, and a long and complicated detection process have limited their use. Despite its limitations, liquid biopsy is a useful tool in clinical decision making and has the potential to play an increasingly important role in the management of breast carcinoma in the future as we move toward more personalized cancer care.