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.