This is a community-based prospective study and the research object is breast cancer patients. It is planned to take the community as the unit to inform and collect the breast cancer patients who voluntarily participate to carry out the detection of BRCA1, BRCA2, PTEN, CHEK2 and PALB2 genes through the community health service center.

This is a population-based, prospective, cohort study which has been ongoing in 3 provinces of eastern China since 2019. Up to 5000 breast cancer survivors will conduct BRCA1, BRCA2, PTEN, CHEK2, and PALB2 genetic susceptibility genes testing, fill in clinical and genetic information forms, and collect family history. Mutation rate of BRCA1/2 and other genetic susceptibility genes in Chinese community breast cancer population will be measured. Logistic regression will be performed to establish a prediction model for the probability of BRCA1/2 and other gene mutations. Kin-Cohort method will be used to calculate the penetrance of breast cancer and other common malignancies in BRCA1/2 and other genetic mutation carriers.

Inclusion Criteria:

• breast cancer patients of any age;
• both male and female;
• the subjects signed the informed consent to participate in the study and abide by the study procedure before being selected.

Exclusion Criteria:

• healthy people or other malignant tumor patients without breast cancer;
• unable to interview the investigator and sign the informed consent due to any reason;
• it is impossible to collect peripheral blood or oral mucosa samples for any reason.

Breast cancer patients from community.