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: A novel gene (designated 121P2A3) and its encoded protein, and variants thereof, are described wherein 121P2A3 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, 121P2A3 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 121P2A3 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 121P2A3 can be used in active or passive immunization.

Abstract: A novel gene (designated 101P3A11 or PHOR-1) and its encoded protein, and variants thereof, are described wherein 101P3A11 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, 101P3A11 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 101P3A11 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 101P3A11 can be used in active or passive immunization.

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: A novel gene (designated 83P2H3) and its encoded protein are described. While 83P2H3 exhibits tissue specific expression in normal adult tissue, it is aberrantly expressed in prostate cancer. Consequently, 83P2H3 provides a diagnostic and/or therapeutic target for cancer. The 83P2H3 gene or fragment thereof, or its encoded protein or a fragment thereof, can be used to elicit an immune response.

Abstract: Novel hematopoietic-restricted tyrosine kinases are provided, where the tyrosine kinases provide for autophosphorylation and transphosphorylation. Modulation of the activity of the subject compositions can be used to restrict growth and differentiation, to correct genetic deficiencies, and to elucidate the activation pathway involved with the subject tyrosine kinases. In addition, the tyrosine kinases may be used in a variety of assays as a label or in the production of the phosphorylated peptides.