Abstract: This invention relates generally to a multimeric polypeptide complex/antigen which may be utilized in detecting or diagnosing diseases of the breast such as breast cancer. Furthermore, the invention relates to methods and kits, for example, which utilize this antigen or an antibody thereto. The complex itself comprises at least one BU101 polypeptide and at least one Mammaglobin polypeptide. In addition, the complex may comprise at least one polypeptide having at least 20% identity with the amino acid sequence of the BU101 polypeptide, the amino acid sequence of the Mammaglobin polypeptide, and fragments thereof.

Abstract: Methods for isolating ZAP-3 genes are provided. Deletion of the ZAP-3 locus is associated with human tumors, particularly carcinomas. The ZAP-3 nucleic acid compositions find use in identifying homologous or related proteins and the DNA sequences encoding such proteins; in producing compositions that modulate the expression or function of the protein; and in studying associated physiological pathways. In addition, modulation of the gene activity in vivo is used for prophylactic and therapeutic purposes, such as treatment of cancer, identification of cell type based on expression, and the like.