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.

Background: Because mesothelioma initially progresses on the surface of the pleura and peritoneum without forming masses, it has been difficult to diagnose at an early stage. It would be very useful to identify a tumor marker that could be used for screening to enable more diagnoses to be made at an early, treatable stage. Materials and Methods: We had previously identified N-ERC/mesothelin as a potential biomarker for mesothelioma. In the current work, we used a newly developed ELISA system to gain data on N-ERC/mesothelin levels in various clinical settings. A total of 102 healthy volunteers were recruited. In addition, 39 patients were diagnosed with mesothelioma, 53 patients were diagnosed with diseases that should be distinguished from mesothelioma, and 201 subjects were diagnosed with asbestos-related nonmalignant diseases (including simple exposure to asbestosis) who were treated at any of the cooperating hospitals were enrolled. Results: Serum N-ERC/mesothelin levels measured by a new ELISA system showed that the median values from patients with mesothelioma were extremely high compared with levels obtained from other patients. Analysis in terms of histologic type showed that serum levels of N-ERC/mesothelin were elevated in epithelioid type mesothelioma, especially. In four important models of clinical settings, the sensitivity and specificity of N-ERC/mesothelin were about 71% to 90% and 88% to 93%, respectively. Conclusion: N-ERC/mesothelin is a very promising tumor marker for mesothelioma, especially epithelioid mesothelioma.Mesothelioma initially progresses along the surfaces of the pleura and peritoneum without forming masses; it is anatomically difficult to diagnose at an early stage and to completely remove with surgery. Moreover, mesothelioma typically has a long incubation period before it becomes clinically evident among high-risk individuals with severe exposure to asbestos. Sugarbaker et al.(1) has reported a groundbreaking result: for patients with early stage disease, 5-year survival after trimodality therapy exceeded 40%. This finding that early disease may be effectively treated emphasizes the importance of identifying a tumor marker that is practical for screening and can allow physicians to make an early diagnosis.Recently, osteopontin, soluble mesothelin-related protein, and serum mesothelin have been reported as candidates for a mesothelioma tumor marker (2 -7). We have postulated (8) that another product may be useful as a tumor marker: N-ERC/ mesothelin, a NH 2 terminal 31-kDa fragment of mesothelin gene products that was first cloned as a megakaryocytepotentiating factor in humans and that is physiologically secreted into blood. Since the time of that report, we have established a new ELISA system that detects the NH 2 terminal fragments of ERC/mesothelin products at a higher sensitivity and specificity. The current work was done to obtain data for Materials and MethodsPreparation of novel anti-ERC/mesothelin antibodies. The anti -N-ERC/mesothelin monoclonal antibody (Mo...

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The aim of this study was to evaluate our personal experience with video-assisted thoracoscopic lobectomy and compare survival between this procedure and conventional lobectomy via open thoracotomy in patients with clinical stage IA non-small cell lung carcinoma. Between May 1997 and December 2004, 140 patients with clinical stage IA non-small cell lung carcinoma had either VATS lobectomy (VATS group, 84 patients) or standard lobectomy via open thoracotomy (open group, 56 patients) performed in our hospital. We compared overall survival, disease-free survival and recurrence between the two groups. The overall survival rate five years after surgery was 72% in the open group and 82% in the VATS group. There were no significant differences in the overall survival rate between the two groups. The disease-free survival rate five years after surgery was 68% in the open group and 80% in the VATS group. There were no significant differences in the disease-free survival rate between the two groups. Five patients in the open group developed distant recurrence, whereas one patient developed regional recurrence. In the VATS group six patients developed distant recurrence, whereas one patient developed regional recurrence. We consider VATS lobectomy to be one of the therapeutic options in patients with clinical stage IA non-small cell lung carcinoma.

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