Scientists are searching for the vital clues that will diagnose mesothelioma early enough to give sufferers a fighting chance. The global search for biomarkers, or biological markers, is key to early diagnosis of mesothelioma, which is known for its long latency before symptoms appear.
Professor Jenette Creaney of the National Centre for Asbestos-Related Disease (NCARD) in Perth says biomarkers help doctors recognise the presence of the cancer before symptoms appear.
“Biomarkers can be almost anything –a protein, a nucleic acid, an enzyme or a sugar – as long as they give an indication of disease,” Prof Creaney said.
“There is huge interest in biomarkers around the world because if you can spot a disease early enough, then you have more options for treating patients. Mesothelioma is usually detected at an advanced stage, where the possibility of a cure is minimal.”
To date, soluble mesothelin-related (or SMR) protein – discovered by Professor Bruce Robinson and the NCARD team in 2004 – remains the best available biomarker for malignant mesothelioma.
But, says Prof Creaney, it is not sensitive enough to pick up the disease in everyone in those vital early stages.
“Mesothelin is better than anything we have at the moment, but it’s not good enough. In advanced disease it is positive in 80 per cent of patients. But at diagnosis it is probably present in only about 50 per cent of patients.”
While studies such as GUARD search for the genes implicated in mesothelioma, Prof Creaney believes that important biomarkers could be found among the body’s proteins or building blocks.
She sees proteomics – the study of proteins – as playing to WA’s strengths: the state has a high-tech Proteomics Facility that makes analysis of proteins possible on an industrial scale and some of the best researchers in this area.
Among other promising proteomics research:
• A group in Colorado in the United States recently announced that it had found 19 protein biomarkers which had yielded promising results in detecting mesothelioma. The team from SomaLogic, led by Dr Rachel Ostroff, launched a year-long validation trial of their discovery last month involving about 400 patients.
• Scientists from Hyogo College of Medicine in Japan have published research on a potential biomarker known as CD146, which they say is present in mesothelioma, prostate cancer and ovarian cancer. (http://www.nature.com/modpathol/journal/v23/n11/abs/modpathol2010134a.html)
• Calretinin, a vitamin D-dependent calcium-binding protein, has been identified as a possible biomarker for mesothelioma by several research groups, including a team at the New York University Medical Center (http://cat.inist.fr/?aModele=afficheN&cpsidt=1414308)
At the Asbestos Disease Research Institute (ADRI) in Sydney, researchers are focusing on microRNAS.
Discovered in the 1990s, these small RNAs act as master regulators of protein synthesis, and, says Dr Glen Reid of ADRI, could be highly effective biomarkers.
“Different tumours produce a unique pattern of microRNAs as the tumour grows,” Dr Reid said.
They are detectable in saliva, urine and blood.
“The problem is that plasma is difficult to work with,” he said. “There is no consistent methodology for isolating and concentrating microRNAs. So we are working on ways to do this.”
He said that early preclinical data has shown that by controlling the levels of specific microRNAs, cancer cell growth may be reduced.
Story by Catherine Madden