A novel gene (designated 125P5C8) and its encoded protein are described. While 125P5C8 exhibits tissue specific expression in normal adult tissue, it is aberrantly expressed multiple cancers including prostate, bladder, kidney and colon cancers. Consequently, 125P5C8 provides a diagnostic and/or therapeutic target for cancers, and the 125P5C8 gene or fragment thereof, or its encoded protein or a fragment thereof used to elicit an immune response.