A new blood test developed in Japan is raising hopes it can more accurately diagnose mesothelioma, leading to earlier cancer treatment and improved chances of survival.
The test involves a protein biomarker in the blood called N-ERC/mesothelin and a new enzyme-linked system for detecting it. This biomarker is overly expressed in patients with the asbestos-related cancer.
Researchers reported their test was 95 percent accurate in identifying cases of the disease and 76 percent accurate in ruling it out. Both are higher percentages than previously reported with other blood tests.
Most experts agree the key to developing better therapies for this disease linked to asbestos exposure is finding better tools to diagnose it earlier. The majority of cases discovered today are too far developed to offer patients a realistic chance of long-term survival.
“The present study demonstrates that this newly established system for N-ERC/mesothelin improved sensitivity and specificity for the diagnosis of pleural mesothelioma,” wrote lead author Tadashi Sato of the Department of Respiratory Medicine at Juntendo University School of Medicine in Tokyo. “We believe that this blood biomarker is an ideal tool for the early diagnosis.”
The study was published in the June issue of Cancer Medicine.
Getting an accurate diagnosis today often takes many months and a variety of often invasive tests. A simple, accurate blood test could lead to early screenings for people with well-known exposure to the toxic mineral, discovering the disease in its infancy when it is much more treatable.
“Early diagnosis of mesothelioma is essential to improving prognosis,” Sato wrote in the findings.
The Japanese researchers said they had studied other blood biomarkers that helped diagnose pleural mesothelioma with a 7-16 enzyme-linked immunosorbent assay system, known as ELISA. But none detected the illness as effectively as N-ERC/mesothelin biomarker with the newer 7-20 ELISA system.
The U.S. Food and Drug Administration in 2007 approved an earlier SMRP (soluble mesothelin-related protein) blood test for monitoring the disease, but never as a diagnostic tool. SMRP is marketed under the trade name Mesomark, but it has a lower accuracy rating compared to the Japanese test.
Researchers also cite the fibulin-3 protein biomarker for its potential, but they haven’t tested either of those biomarkers under their revised ELISA system.
“We should consider comparing them to N-ERC/mesothelin levels as a next step,” Sato wrote.
The latest study shows the N-ERC testing is more accurate when used in blood plasma and not serum. It’s also more effective in diagnosing epithelial mesothelioma, the most common, most treatable kind, as opposed to sarcomatoid or biphasic types.
Study participants included 53 patients referred to the Juntendo School of Medicine between from 2005 to 2013. They were suspected of having the illness based on pleural thickening, pleural effusion and a history of asbestos exposure.
Their levels of N-ERC/mesothelin were obtained in daily clinical practice, prior to a final diagnosis, which included 28 patients with mesothelioma and 25 with another condition.
“The current study is limited by the small number of patients. Since this is a rare disease, it is difficult to recruit sufficient patients from a single department,” Sato wrote. “A multicenter clinical trial is needed to fully evaluate the diagnostic potential.”
Researchers said developing this new blood test to detect mesothelioma more accurately is a great start for offering patients treatment much sooner, their next step is combining the N-ERC/mesothelin with other biomarkers for even better results.