A novel gene (designated 213P1F11) and its encoded protein, and variants thereof, are described wherein 213P1F11 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, 213P1F11 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 213P1F11 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 213P1F11 can be used in active or passive immunization.