Tumor biomarkers are substances that are produced or elevated abnormally by tumor cells during tumorigenesis and proliferation or by patients in response to cancer, reflecting the presence and growth of tumors. This concept was introduced by Herberman in 1978 at the conference “Human Immunity and Tumor Immunodiagnosis” held at the National Cancer Institute (NCI) in the United States, and was recognized by scholars at the 7th Conference on the Biology and Medicine of Oncogenesis in the United Kingdom the following year. The following year, it was recognized and started to be cited by scholars at the 7th Conference on the Biology and Medicine of Oncogenesis in the UK. The ideal clinical tumor markers should have the following characteristics: 1. high specificity: the elevation of tumor markers indicates a definite tumor that can be clinically diagnosed; 2. high sensitivity: the abnormal increase of tumor markers can be detected at the early stage of tumor; 3. the elevation of tumor markers has a direct and positive relationship with the growth and metastasis of tumor; 4. Tumor markers are simple, low cost and easy to promote, especially in body fluids or blood. The occurrence and development of breast cancer are regulated by multiple genes, which makes breast cancer present complex and diverse forms in terms of clinical manifestations, histological types and molecular immunophenotypes. At present, the corresponding tumor markers performed clinically for breast cancer are mainly: CEA, CA153, CA125, etc. Due to the low specificity and sensitivity of these tumor markers related to breast cancer, the clinical detection of breast cancer-related tumor markers does not reach the ideal clinical application state as mentioned before. Generally, for patients with elevated tumor markers before breast cancer surgery and decreased marker levels after surgery, tumor marker monitoring can be used for clinical follow-up and early detection of recurrence and metastasis. In addition, because breast cancer patients have tumor susceptibility, the monitoring of these tumor markers can be used as a basis for screening other tumor diseases. Therefore, at present, imaging review is more clinically relevant than tumor marker review for periodic review after initial breast cancer treatment. Tumor marker review is not necessarily a mandatory item for breast cancer review.