New results presented at 3rd European Lung Cancer Conference in Geneva, Switzerland show important steps being made to improve the diagnosis and treatment of malignant pleural mesothelioma, an aggressive cancer of the outer lining of the lungs caused by asbestos exposure. Micro RNAs speed diagnosis Australian researchers have identified a small molecule that is more abundant in the blood of people with the deadly lung disease mesothelioma than in healthy people. Their findings bring scientists a step closer to being able to diagnose mesothelioma earlier than is currently possible. At present diagnosing mesothelioma depends on the availability of a lung biopsy that contains enough tumor tissue. However suitable biopsies are not always available, which can leave doctors uncertain about the patient\'s diagnosis, sometimes resulting in a delay to the start of treatment. \"If doctors could use a diagnostic marker based on a simple blood test to help with diagnosis, it could circumvent the problem of availability of tumor tissue and help to accelerate the diagnostic process,\" says Dr Michaela Kirschner from the Asbestos Diseases Research (Concord Hospital Campus) in Sydney, who reported the new findings. So far a number of proteins have been proposed as blood-based markers for malignant pleural mesothelioma; however none of these has so far reached the accuracy required for routine clinical use. In the new study, Dr Kirschner and colleagues explored whether molecules known as microRNAs in blood could serve as a diagnostic marker for the disease. Studying 5 patients with malignant pleural mesothelioma and 3 healthy controls, they identified 17 microRNAs with significantly differential abundance in the two groups. They then validated these miRNAs in a series of blood samples from 15 patients and 13 controls. These studies revealed that the level of a particular microRNA known as miR-625-3p was four-fold higher in the blood of mesothelioma patients. Measuring levels of that molecule in blood samples allowed the researchers to discriminate between MPM patients and controls with an accuracy of 82.4%. \"Detailed analyses of our two independent sample series have shown that miR-625-3p performs as well as any previously proposed protein marker for detecting mesothelioma,\" Dr Kirschner said. \"However, like most diagnostic markers, miR-625-3p is not 100% accurate, and therefore there is a chance the assay will produce both false positives as well as false negatives. Further studies on larger sample sizes are needed to see whether the accuracy of miR-625-3p can be confirmed or even turn out to be better than currently observed.\" \"Should further studies prove that microRNAs in plasma are accurate enough for the diagnosis of malignant pleural mesothelioma, this will lead to the development of a diagnostic test for routine clinical use,\" Dr Kirschner said. \"This test would then represent a relatively simple way to circumvent the problems associated with obtaining a tissue biopsy. For a patient this would mean that appropriate treatment could be instituted at an earlier stage.\"