A novel gene (designated 101P3A11 and also referred to as PHOR-1) and its encoded protein are described. While 101P3A11 exhibits tissue specific expression in normal adult tissue, it is aberrantly expressed in prostate, colon and kidney cancers. Thus, 101P3A11 provides a diagnostic, prognostic, prophylactic and/or therapeutic target for cancer. The 101P3A11 gene or fragment thereof, or its encoded protein or a fragment thereof, can be used to elicit an immune response.