Full Title: “Sensitive and Specific New Enzyme-Linked Immunosorbent Assay for N-ERC/Mesothelin Increases its Potential as a Useful Serum Tumor Marker for Mesothelioma”

The early diagnosis of mesothelioma is a crucial element in achieving the best prognosis. If the disease is discovered in its beginning stages it can be treated with aggressive tri-modal therapy, which may extend a person’s life significantly beyond the typical range of mesothelioma survivors. The problem, however, is that mesothelioma is difficult to diagnose in the early stages. It shares many common symptoms with less serious conditions and often goes undiagnosed until its more serious effects arise during the disease’s advanced stages. Diagnoses are also missed because the diffuse malignancy pattern typical of standard-form pleural mesothelioma means the cancer’s growth is often overlooked or not even rendered by imaging technologies during the disease’s earliest stages. What is needed—and is sorely lacking—is the development of a simple test that can easily return a diagnosis or at least an indication that mesothelioma may be at work.

A variety of research projects are actively working on just this issue, with the development of tumor makers specific to mesothelioma among the most important. A tumor marker is a diagnostic tool that can be used to easily test for the presence of a particular malignancy in the blood of patient or in a tissue sample not otherwise indicative of cancer. A number of markers have been proposed for mesothelioma diagnosis and researchers around the world are busy looking for the most effective ones. In 2006, a group of doctors and researchers from Japan proposed the use of N-ERC/mesothelin as another potential tumor marker for malignant pleural mesothelioma. These researchers have recently published an update to their original work that describes the development of an improved enzyme-linked immunosorbent assay (ELISA) system with a higher sensitivity and specificity for the detection of N-ERC/mesothelin in a blood sample.

Overview of the Study

To study the diagnostic value of N-ERC/mesothelin and the efficacy of their improved ELISA system, the authors enrolled 293 patients into their study. 39 patients presented with histologically-confirmed mesothelioma, 201 with an asbestos-related illness that was not mesothelioma, 45 with lung cancer and 8 with other malignancies. A group of 102 healthy people were used as a control group.

To establish baseline N-ERC/mesothelin levels, the authors first analyzed the group of healthy patients, who showed generally uniform levels without any statistically significant differences based on sex or smoking status, although there was some correlation between older patient age and increased N-ERC/mesothelin levels.

When the authors moved to the study of the mesothelioma group, they found significant correlation between this group and high N-ERC/mesothelin levels. Median levels for the mesothelioma cohort were significantly greater than the levels found in all other patient groups. They found that within this cohort, patients who presented with epitheloid mesothelioma demonstrated especially high levels. They also discovered a correlation between higher N-ERC/mesothelin levels and advanced stage disease. All of these results clearly point to the continued study of N-ERC/mesothelin as a tumor marker for mesothelioma.

Conclusion

It is hoped that the development of specific tumor markers will enable more diagnoses of early stage mesothelioma—a time when the disease appears much more responsive to therapy than it does in its later stages. The authors noted an article by David Sugarbaker that said patients who received aggressive tri-modal therapy during the early stages of the disease demonstrated a 5-year survival figure exceeding 40%. For a disease known mainly for its poor prognosis, a demonstration of 5-year survival figures is truly a cause for hope.

The authors conclude the paper stating that their use of N-ERC/mesothelin and the improved ELISA system has demonstrated clear diagnostic value and they call for more research into potential tumor markers. While confirmation of their findings must be made by independent researchers before we can definitively establish the efficacy of their system, everyone agrees that the development of a simple blood test for mesothelioma is one of the great goals of current mesothelioma research. Such a development would truly revolutionize the manner in which the disease would be treated, as patients could begin therapy much sooner than they currently do.

Labels: mesothelioma