Novel ELISA system for detection of N‐ERC/mesothelin in the sera of mesothelioma patients

We have developed a novel enzyme‐linked immunosorbent assay (ELISA) system for the detection of N‐ERC/mesothelin in the serum of mesothelioma patients and have begun to examine its clinical usefulness. N‐ERC/mesothelin is a 31‐kDa protein that forms the N‐terminal fragment of the full‐length 71‐kDa ERC/mesothelin protein, and is physiologically secreted into the blood of mesothelioma patients where it can be detected using our sandwich ELISA containing two antibodies (rabbit polyclonal anti‐ERC/mesothelin antibody‐282 and mouse monoclonal antibody 7E7). Our ELISA system has thus far detected much higher serum levels of N‐ERC/mesothelin in mesothelioma patients than in healthy controls or patients with other lung or pleural diseases. In conclusion, N‐ERC/mesothelin is a promising candidate tumor marker for mesothelioma. (Cancer Sci 2006; 97: 928–932)