This invention relates to a novel target for production of immune and non-immune based therapeutics and for disease diagnosis. More particularly, the invention provides therapeutic antibodies against C1ORF32 antigens, which are predicted co-stimulatory family members and which are differentially expressed in cancers including, lung cancer, ovarian cancer, and colon cancer, and diagnostic and therapeutic usages. The use of these antibodies for modulating B7 costimulation is also provided. This invention further relates to the discovery of extracellular domains of C1ORF32 and its variants awhich are suitable targets for cancer therapy, and drug development.
