Open Access Research article

Serological identification of Tektin5 as a cancer/testis antigen and its immunogenicity

Tadashi Hanafusa1, Ali Eldib Ali Mohamed25, Shohei Domae3, Eiichi Nakayama4 and Toshiro Ono1*

Author Affiliations

1 Department of Radiation Research, Advanced Science Research Center, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan

2 Zoology Department, Faculty of Science, Damanhour University, Damanhour, Egypt

3 Department of Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan

4 Faculty of Health and Welfare, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama, 701-0193, Japan

5 Batterjee Medical College (BMC), P.O 6231, Jeddah, 21442, Kingdom of Saudia Arabia

For all author emails, please log on.

BMC Cancer 2012, 12:520  doi:10.1186/1471-2407-12-520

Published: 14 November 2012



Identification of new cancer antigens is necessary for the efficient diagnosis and immunotherapy. A variety of tumor antigens have been identified by several methodologies. Among those antigens, cancer/testis (CT) antigens have became promising targets.


The serological identification of antigens by the recombinant expression cloning (SEREX) methodology has been successfully used for the identification of cancer/testis (CT) antigens. We performed the SEREX analysis of colon cancer.


We isolated a total of 60 positive cDNA clones comprising 38 different genes. They included 2 genes with testis-specific expression profiles in the UniGene database, such as TEKT5 and a CT-like gene, A kinase anchoring protein 3 (AKAP3). Quantitative real-time RT-PCR analysis showed that the expression of TEKT5 was restricted to the testis in normal adult tissues. In malignant tissues, TEKT5 was aberrantly expressed in a variety of cancers, including colon cancer. A serological survey of 101 cancer patients with different cancers by ELISA revealed antibodies to TEKT5 in 13 patients, including colon cancer. None of the 16 healthy donor serum samples were reactive in the same test.


We identified candidate new CT antigen of colon cancer, TEKT5. The findings indicate that TEKT5 is immunogenic in humans, and suggest its potential use as diagnostic as well as an immunotherapeutic reagent for cancer patients.

TEKT5; SEREX; CT antigen