In one embodiment, a method of theranostic classification of a breast cancer tumor is provided, comprising obtaining a breast cancer tumor sample from a subject, detecting an expression level of FOXC1, comparing the expression level of FOXC1 to a predetermined cutoff level, and classifying the breast cancer tumor sample as belonging to a theranostic basal-like breast cancer tumor subtype or a theranostic hybrid basal-like breast cancer tumor subtype when the expression level of FOXC1 is higher than the predetermined cutoff level. In other embodiments, methods for predicting a prognosis of a basal-like breast cancer and methods of treating a basal-like breast cancer are provided.