Abstract: The invention provides isolated nucleic acids that encode prostate cancer candidate protein 1 (PCCP1), and fragments thereof, vectors for propagating and expressing PCCP1 nucleic acids, host cells comprising the nucleic acids and vectors of the present invention, proteins, protein fragments, and protein fusions of the novel PCCP1 isoforms, and antibodies thereto. The invention further provides transgenic cells and non-human organisms comprising human PCCP1 nucleic acids, and transgenic cells and non-human organisms with targeted disruption of the endogenous orthologue of the human PCCP1 gene. The invention further provides pharmaceutical formulations of the nucleic acids, proteins, and antibodies of the present invention, and diagnostic, investigational, and therapeutic methods based on the PCCP1 nucleic acids, proteins, and antibodies of the present invention.