Abstract: Disclosed herein is a method for treating a subject having, or at risk of having, a triple negative breast cancer, comprising administering to the subject a therapeutically effective amount of an immunotherapeutic agent and a tumor membrane vesicle (TMV), wherein the TMV comprises a lipid membrane, and a B7-1 and/or IL-12 molecule anchored to the lipid membrane. Also disclosed is method for predicting the likelihood a human subject having a cancer will respond therapeutically to a TMV immunotherapy, wherein the method comprises obtaining a blood or serum sample from the subject; measuring the amount of a set of biomarkers in the sample, wherein the biomarkers include at least IFN-gamma, TNF-alpha, and IL-2, and wherein an increase in the level of the biomarkers as compared to a control indicates an increased likelihood the subject will respond therapeutically to the TMV immunotherapy.