APOA1 and breast cancer: Polymorphisms of APOA1/C3/A4/A5 have been demonstrated to be associated with metabolic syndrome, dyslipidemia, and cardiovascular diseases.18,34,35 Among them, the APOA1 protein has been extensively studied and has been demonstrated to protect against tumor development or progression in several cancers.26,36,37 Serum APOA1 level is also negatively associated with higher breast cancer risk38 and recurrence39.