Human basal-like breast cancer is represented by one of the two mammary cancer subtypes in dogs

About 20% of breast cancers in humans are basal-like, a subtype that is often triple negative and difficult to treat. An effective animal model for basal-like breast cancer is currently lacking and urgently needed. To determine if naturally occurring mammary tumors in pet dogs could meet this need, we subtyped canine mammary tumors and evaluated the dog-human molecular homology at the subtype level. Our study identifies a canine mammary tumor subtype that molecularly resembles human basal-like breast cancer overall, and thus could serve as a much-needed spontaneous animal model of this devastating breast cancer subtype.