Mesothelioma is often diagnosed in the more advanced stages, when symptoms have appeared and patients are seeking relief. Taking a look inside the chest cavity (or abdominal cavity, depending on where symptoms occur) is currently the best way to determine if mesothelioma is the cause — finding and testing any mass that is spotted. But research is being done on better methods of mesothelioma diagnosis to help detect the disease earlier, and in a less invasive way. Mesothelioma: Current Methods of Diagnosis Right now, the most common method of detecting mesothelioma is video-assisted thoracoscopy, a surgical procedure in which a scope is inserted through a small incision in the chest wall. "At the same time that we pass the scope into the chest to look around, we can take direct biopsies of the chest wall," explains David Rice, MD, an associate professor and director of the mesothelioma program at the University of Texas M.D. Anderson Cancer Center. "That is probably the most definitive way that mesothelioma is diagnosed." Other common diagnostic tests are: X-rays Computed tomography (CT) scans Magnetic resonance imaging (MRI) scans Positron emission tomography (PET) scans Thoracotomy — a major incision in the chest to view the inside of the chest cavity A biopsy of the tissue or fluids inside the chest or abdomen is also often performed. But now, pathologists — doctors trained in laboratory medicine who make a diagnosis by looking at the biopsies under a microscope — might have more clues to look for in those samples. Mesothelioma: New Diagnostic Tests Blood, tissue, and fluid samples from people with suspected mesothelioma can now be studied in new ways to diagnose — or confirm a diagnosis — of mesothelioma. Here are some new diagnostic tests being studied or used today for mesothelioma: Immunohistochemical markers: After a chest X-ray finds fluid in the chest and the fluid is drained, says Dr. Rice, that fluid will be sent to a lab and analyzed to see if there are cancer cells. If they’re detected, then further study, called immunohistochemistry, is conducted to see if those cancer cells are mesothelioma or another type of cancer. These immunohistochemical markers can help define — or rule out — mesothelioma. A marker is a biological substance that is present in a certain disease; different diseases have different characteristics. In the case of mesothelioma, molecules such as cytokeratin 5, an antibody, and thrombomodulin, a type of protein found in epithelial cells, will be present. Different markers would be present if the diagnosis was lung cancer from smoking, for example. SMRP: Soluble mesothelin-related peptides (SMRP) are markers that can diagnose mesothelioma. SMRP are products that are broken down from the proteins in the chest and abdominal cavity linings. A blood test can measure the level of SMRP in the blood; higher-than-normal levels often indicate mesothelioma. The SMRP test is usually used in conjunction with a PET, CT, or MRI imaging test. And most often, the test is used to see how effectively treatment is working, if the cancer has returned, or if it has spread throughout the body. Glycoprotein markers: Glycoproteins are other markers used to evaluate mesothelioma. These proteins are found in the membranes lining the chest and abdominal cavities. A blood test to look for levels of glycoproteins in the blood, like osteopontin (one type of glycoprotein marker) may be used to help confirm a diagnosis of mesothelioma. More often, glycoprotein blood tests measure disease progression. Osteopontin levels, for example, are expected to fall if treatment is working and increase if it is not. This can help physicians determine if treatment is effective, or if the cancer is spreading or recurring. These blood tests are important advances in diagnosing mesothelioma because they are a minimally invasive method of confirming suspicions of a mesothelioma diagnosis. "You want to avoid a major surgical procedure just for diagnosis," says Rice. "Diagnosis of mesothelioma should be based on a high level of clinical suspicion," with a history of asbestos exposure and X-rays that indicate warning signs of mesothelioma. In those individuals, these more advanced blood tests can confirm what personal history, symptoms, and imaging tests indicate — a diagnos