PRKCD and breast cancer: The idea that PKCη could serve as a target for therapy in breast cancer is further supported by our recent report of an upstream open reading frame (uORF)-encoded micropeptide in the 5′UTR on the mRNA coding for PKCη that acts in cis as a kinase inhibitor for PKCη and in trans for other novel PKC family members (PKCδ, ε, θ), but not for classical or atypical PKCs [36].