Abstract: The present invention relates to agonist antibodies that specifically bind to Notch 3 and activate signaling. The present invention includes antibodies binding to an epitope comprising the first Lin12 domain. The present invention also includes uses of these antibodies to treat or prevent Notch 3 related diseases or disorders.

Abstract: Described is a novel family of cell surface serpentine transmembrane antigens. Two of the proteins in this family are exclusively or predominantly expressed in the prostate, as well as in prostate cancer, and thus members of this family have been termed “STEAP” (Six Transmembrane Epithelial Antigen of the Prostate). Four particular human STEAPs are described and characterized herein. The human STEAPs exhibit a high degree of structural conservation among them but show no significant structural homology to any known human proteins. The prototype member of the STEAP family, STEAP-1, appears to be a type IIIa membrane protein expressed predominantly in prostate cells in normal human tissues. Structurally, STEAP-1 is a 339 amino acid protein characterized by a molecular topology of six transmembrane domains and intracellular N- and C-termini, suggesting that it folds in a “serpentine” manner into three extracellular and two intracellular loops.

Abstract: Antibodies and molecules derived therefrom that bind to novel STEAP-1 protein, and variants thereof, are described wherein STEAP-1 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, STEAP-1 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The STEAP-1 gene or fragment thereof, or its encoded protein, or variants thereof, or a fragment thereof, can be used to elicit a humoral or cellular immune response; antibodies or T cells reactive with STEAP-1 can be used in active or passive immunization.

Abstract: A novel gene 098P4B6 (also designated STEAP-2) and its encoded protein, and variants thereof, are described wherein 98P4B6 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, 98P4B6 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 98P4B6 gene or fragment thereof, or its encoded protein, or variants thereof, or a fragment thereof, can be used to elicit a humoral or cellular immune response; antibodies or T cells reactive with 98P4B6 can be used in active or passive immunization.