Triple-negative breast cancer (TNBC) is histologically defined by a lack of estrogen receptor and progesterone receptor expression and the absence of human epidermal growth factor receptor 2 overexpression and/or amplification

accounting for 10%-20% of all diagnosed breast cancers. As a group

patients with TNBC have a relatively poor outcome

including high incidence of relapse

early metastasis and poor effect of chemotherapy in advanced stage

and are more prone to visceral metastasis

especially lung and brain metastases. Compared with other subtypes of breast cancer

TNBC are frequently of higher histologic grade and poorer prognosis

which has always been the focus and difficulty of clinical research. In the era of precision medicine

with the application of gene detection technology

the classification of TNBC is more accurate

and there are many kinds of treatment

such as targeted therapy and immunotherapy. This review described the latest development in TNBC.