As mesothelioma is a form of cancer which progresses very rapidly, timely detection is essential for higher survival rates. The prognosis for mesothelioma patients is five times more favorable when the disease is diagnosed at stage 1 than at stage 4. However, early diagnosis is quite problematic in the case of mesothelioma, as people who suffer from it rarely experience symptoms before cancer reaches an advanced stage. Only 25% of mesothelioma patients are eligible to undergo aggressive surgery, whereas the average life expectancy ranges between 6 and 18 months.

While a series of blood tests which, in combination with other diagnostic tools, can indicate whether a person has mesothelioma are currently available, their accuracy is not very high. For instance, approximately 84% of those whose MESOMARK assay results show elevated SMRP levels actually have mesothelioma. Since there is no foolproof method of determining the presence of mesothelioma within the body, pathologists are examining multiple biomarkers before assigning a diagnosis at the moment.

The number of people struggling with mesothelioma has been relatively steady for the past three decades, as the effects of past asbestos exposure continue to surface. Worldwide, researchers are striving to develop more effective methods of timely identifying mesothelioma, so that early diagnosis and, implicitly, long-term survival will be possible. A team of researchers from Australia and Germany has recently discovered that a blood test measuring the levels of calretinin – a calcium-binding protein whose concentration becomes higher when pleural mesothelioma is occurring – could help specialists detect this form of cancer earlier.

Calretinin is typically produced in excess by epithelioid and biphasic mesothelioma tumors and thereby, a blood test which accurately measures the blood levels of this protein may be invaluable in regard to timely diagnosis. The study, led by Dr. Georg Johnen of the Institute of the Ruhr University Bochum, revealed that a calretinin-based blood test can correctly identify pleural mesothelioma in 71% of cases, which is a slightly higher accuracy rate than that of the biomarker mesothelin (69%).

Moreover, a blood test combining calretinin and mesothelin was found to be remarkably effective in diagnosing mesothelioma. When the biomarkers were used together, calretinin increased the sensitivity of mesothelin with 9%, while this test was also able to rule out mesothelioma with a 97% accuracy rate. “Molecular markers like calretinin and mesothelin are promising tools to improve and supplement the diagnosis of malignant mesothelioma and warrant further validation in a prospective study”, wrote Dr. Johnen in BMC Cancer, where the study was published on May 30 of this year.

The participants were 163 Australian men and 36 German men diagnosed with pleural mesothelioma. Additionally, 235 individuals suffering from non-malignant asbestos diseases, such as pleural plaques or asbestosis, took part in this study as a control group. Prior to treatment, blood serum and plasma samples were collected from each patient in order to measure their levels of calretinin and mesothelin. On average, the values of calretinin in mesothelioma participants were 10 times higher than those of individuals diagnosed with non-malignant diseases caused by asbestos exposure.

Nevertheless, the calretinin-based blood test has proved to be inefficient in the detection of sarcomatoid mesothelioma, the rarest and most unresponsive to treatment subtype. Another study focusing on molecular markers in individuals with a history of occupational asbestos exposure conducted by the same research team – which has been ongoing for approximately 10 years – is close to completion.