Cancer-testis (CT) antigens have been identified by screening public databases for transcripts that are expressed in tumor tissues and a limited set of normal tissues, or by screening for genes that are expressed in cancer and testis tissues (but not other normal tissues). The invention relates to nucleic acids and encoded polypeptides which are CT antigens expressed in patients afflicted with cancer. The invention provides, inter alia, isolated nucleic acid molecules, expression vectors containing those molecules and host cells transfected with those molecules. The invention also provides isolated proteins and peptides, antibodies to those proteins and peptides and cytotoxic T lymphocytes which recognize the proteins and peptides. Fragments of the foregoing including functional fragments and variants also are provided. Kits containing the foregoing molecules additionally are provided. The molecules provided by the invention can be used in the diagnosis, monitoring, research, or treatment of conditions characterized by the expression of one or more CT antigens.