Blood plasma biomarkers for bevacizumab combination therapies for treatment of breast cancer

A method of determining whether a patient diagnosed with HER2 positive breast cancer is more or less suitably treated by an anti-cancer therapy comprising an anti-VEGF antibody, the method comprising: (a) determining an expression level of VEGFA and/or VEGFR2 in a sample derived from a patient diagnosed with HER2 positive breast cancer, and (b) identifying the patient as more or less suitably treated by an anti-cancer therapy comprising an anti-VEGF antibody based on the expression level in accordance with (a), wherein an expression level of VEGFA and/or VEGFR2 at or above a reference level indicates that the patient is more suitably treated with the anti-cancer therapy, or an expression level of VEGFA and/or VEGFR2 below a reference level indicates that the patient is less suitably treated with the anti-cancer therapy.