Malignant mesothelioma is on the rise around the world. As with many cancers, early detection is the key to survival and better quality of life for patients. Now, a group of Japanese researchers is paving the way for a laboratory test that could help doctors identify the disease – and start aggressive treatment – earlier.
Writing in the journal, Modern Pathology, the researchers explain how a protein called CD146 can serve as a biomarker for mesothelioma. The protein has already been shown to be present in patients with advanced malignant melanoma, prostate cancer and ovarian cancer. Now, for the first time, researchers have also identified its presence in the lung fluid of mesothelioma patients.
The research team tested the lung fluid of 51 patients; 23 had malignant mesothelioma and 28 had a benign lung condition called reactive mesothelium. Although patients had similar symptoms and all had fluid build-up, only the malignant mesothelioma patients tested positive for the presence of CD146. The researchers reported that the protein was undetectable in all cases of reactive mesothelium. They were able to use CD146 to identify and confirm 90 percent of the patients with malignant mesothelioma.
Caused exclusively by exposure to asbestos, mesothelioma is notoriously difficult to diagnose. Its symptoms, which can include shortness of breath and coughing, can mimic many other diseases and even CT scans are often not definitive. As a result, some cases of mesothelioma are not identified until the disease is in its advanced stages and treatment options are limited. The Japanese researchers wrote “We propose that CD146 is a sensitive and specific immunocytochemical marker enabling differential diagnosis of malignant pleural mesothelioma from reactive mesothelium.”
According to the World Health Organization, mesothelioma claims the lives of 100,000 people around the world annually and The National Cancer Institute reports that 2,500 to 3,000 of those deaths occur in the U.S. Conventional treatments, including chemotherapy, radiation and surgery have not been shown to dramatically prolong survival. Although promising new treatments are under investigation, their success may hinge on the earliest possible detection of the disease.
Sato, Ayuko et al, “Immunocytochemistry of CD146 is useful to discriminate between malignant pleural mesothelioma and reactive mesothelium”, July 23, 2010. Modern Pathology. Advanced online publication.
SEER Cancer Statistics Review, 1975-2007, National Cancer Institute. Bethesda, MD, Based on November 2009 SEER data submission, posted to the SEER website, 2010.