Selective expression of the Sp17/AKAP4/PTTG1 in NSCLC for detection and therapy

Background: Cancer testis antigens (CTA) are a class of tumor associated antigens, showing a restricted expression in cancer, strong immunogenicity, and weak expression in normal tissues. Sp17/AKAP4/PTTG1 have been previously investigated, showing promising results as a target antigens. Our aim was to investigate the expression of Sp17/AKAP4/PTTG1 in lung cancer patients. Methods: We analyzed two lung cancer cell lines, one normal bronchus cell line, a panel of normal tissues and patient’s cells by RT-PCR, flow-cytometry, immunocytochemistry (ICC), and immunofluorescence (IF). CTA immunogenicity was investigated by measuring circulating specific antibodies in the sera of lung cancer patients. Results: ELISA analyses show the presence of circulating CTA-specific antibodies in the sera of lung cancer patients, indicating the immunogenicity of Sp17, AKAP-4 and PTTG-1. We showed that CTA, Sp17, AKAP-4 and PTTG-1 can be detected in both sera and tissue of patients with NSCLC. Furthermore, CTA can elicit an immunogenic response in patients affected with this disease. Conclusions: Our results provide the first evidence that the CTAs SP17/AKAP4/PTTG1 are expressed in both non-small cell lung cancer cell lines and primary tumor tissues and can elicit an immunogenic response in patients afflicted with this disease. Based on our findings we believe further studies are warranted to explore the feasibility of developing CTA-tailored immunotherapeutic strategies for non-small cell lung cancer.