Blood Protein Predicts Treatment Response in Mesothelioma

A blood protein that is overexpressed in mesothelioma tumor cells may be one of the best ways to predict how well a patient will respond to treatment.

is a serious malignancy of the mesothelium, or tissue that surrounds and encases the lungs, abdomen or heart.  It is almost always caused by exposure to the mineral asbestos.  A protein called mesothelin, which is present in all mesothelial cells, is produced in greater amounts by cancerous mesothelial cells.  Scientists have long believed that this protein may be an important way to gain information about a patient’s mesothelioma cancer.

A study recently published in the journal Clinical Cancer Research appears to confirm that idea.  A group of Australian researchers enrolled 97 mesothelioma patients in the study.  They compared their mesothelin levels to the stage of their tumors, the presence of metastatic (spreading) disease, the results of their PET scans, tumor volume, total glycolytic volume and survival.  As patients went through chemotherapy, changes in their mesothelin levels were monitored and were compared to their progress as determined by X-rays and PET scans.

The results of the study were clear: mesothelioma patients with a baseline mesothelin level higher than 5nM tended to have higher tumor stage and volume to start with, and were not likely to do well, even with treatment.  In 55 mesothelioma patients who received chemotherapy, those whose tumors showed a positive response on X-ray also had a drop in their mesothelin levels.  The median survival for these patients, whose mesothelin levels dropped after chemotherapy, was about 19 months – significantly longer than for those patients whose mesothelin stayed the same or rose.

The researchers concluded that mesothelin remains a valuable tool for determining the prognosis of mesothelioma patients and for monitoring their response to treatment.

Approximately 3,000 cases of mesothelioma are diagnosed in the United States each year.  With an average latency of 20 to 50 years after asbestos exposure, and the tendency of the disease to mimic less serious conditions, diagnosis and prognosis can be extremely challenging.

Sources:

Creaney, J et al, “Serum soluble mesothelin concentrations in malignant pleural mesothelioma: relationship to tumor volume, clinical stage and changes in tumor burden”, December 21, 2010, Clinical Cancer Research. Epub ahead of print.