The purpose of this study is to construct an auxiliary diagnostic model for breast cancer by methylation markers. The study will collect blood and tissue samples from participants with breast cancer and benign disease for whole-genome methylation sequencing. It will screen methylation markers and develop a methylation auxiliary diagnosis model to distinguish between breast cancer and non-cancer.

Inclusion Criteria for All the Participants:

• With confirmed pathological diagnosis and molecular subtyping results
• Ability to provide a written informed consent

Exclusion Criteria for Cancer Arm Participants:

• Patients with a history of or currently suffering from other malignancies
• Pregnant or planning to become pregnant female patients
• Patients who have received cancer treatment, including surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy, before blood draw
• Patients with a history of blood transfusion within the past month
• Patients with a known history of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation
• Patients with persistent fever or undergoing anti-inflammatory treatment within 14 days before blood draw
• Any other conditions that the researcher deems may make the patient unsuitable for inclusion in the study or may interfere with the completion of the study
• Patients in poor physical condition who are not suitable for blood draw
• Patients who cannot provide informed consent or refuse blood draw

Exclusion Criteria for Benign Diseases Arm Participants:

• History of malignancies
• Current malignancies or precancerous lesions

Eligible participants will be recruited from medical centers and assigned into two arms, including participants with new diagnosis of breast cancer and benign diseases.