A novel gene (designated 108P5H8) and its encoded protein, and variants thereof, are described wherein 108P5H8 exhibits tissue specific expression in normal adult tissue, and is aberrantly expressed in the cancers listed in Table I. Consequently, 108P5H8 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 108P5H8 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 191P1E1B can be used in active or passive immunization.