A study has tried to overcome the challenges in the diagnosis of patients with malignant pleural mesothelioma (MPM) through the detection of two biomarkers in pleural effusions and in peripheral blood samples.
The researchers evaluated the levels of tumor cells and of endothelial cells (cells lining the inside of the blood vessels) freely circulating in samples of either pleural effusions or peripheral blood of MPM patients, to serve as a diagnosis for the disease.
The study, “Improved diagnosis and prognostication of patients with pleural malignant mesothelioma using biomarkers in pleural effusions and peripheral blood samples – a short report,” was published in Cellular Oncology.
Diagnosing MPM is still challenging, and while markers to improve diagnosis, like mesothelin, have been described, they are not widely used in the clinic.
Circulating tumor cells, detected in the blood of patients with solid tumors, have been described as prognostic factors for various tumor types. Similarly, high numbers of endothelial cells in circulation also have been associated with solid malignancies.
In this study, researchers aimed to optimize techniques to detect circulating tumor and endothelial cells in the blood and in pleural effusions of MPM patients.
A total of 49 patients were included in this clinical study, 27 of those were patients with confirmed MPM, presenting pleural effusions and a need to undergo pleural drainage. The majority of the patients (81 percent) had an epithelial type MPM.
The other 22 patients worked as a control group. These participants had a diagnosis other than MPM, but had pleural effusions with a need to drain as part of standard care.
Tumor cells circulating in peripheral blood samples were detected in 26 percent of MPM patients, and, in 42 percent of the participants, the number of circulating endothelial cells exceeded the limit established as normal.
When it comes to the pleural effusion samples, the authors reported that the usual fluid cytological test was not as sensitive in the detection of circulating tumor cells as flow cytometry, a widely used laboratory technique that allows counting and sorting of cells.
Results show that the standard test detected tumor cells freely circulating in the fluid from the pleural effusions in 15 percent of MPM patients, while flow cytometry detected circulating tumor cells in 48 percent of MPM patients.
The worse overall survival cases were associated with the absence of circulating tumor cells in the samples of pleural effusions and an amount of circulating endothelial cells in the patients’ peripheral blood that is above the normal limit.
These findings “may serve as a promising approach for the prognostication of MPM patients and, therefore, warrants further study,” the study authors concluded.