A new study sheds light on the role of lung fluid that builds up in many people with mesothelioma, providing evidence that the liquid contains substances that further contribute to malignancy.
The report, “Malignant pleural fluid from mesothelioma has potent biological activities,“ appeared in the journal Respirology.
Malignant pleural effusion refers to the abnormal fluid that builds up between the lining of the outside of the lung (pleura) and the chest cavity wall. Researchers do not completely understand the role of this fluid, and whether it is the consequence of disease or actually contributes to the formation of cancerous cells has been a matter of debate.
The investigators, led by Hui Min Cheah of the Pleural Medicine Unit, Institute for Respiratory Health in Perth, Australia, analyzed fluid samples from 151 patients, including 56 with mesothelioma, 60 with metastatic pleural cancer (lung cancer that has spread), and 35 non-cancerous samples.
They also studied seven human mesothelioma cell lines and three primary cultured mesothelioma cell lines — cells taken directly from a tumor.
Cultured cancer cells in contact with lung fluid from mesothelioma patients had increased proliferation and migration rates, a process similar to cancer spreading in the body. The fluid also induced the growth of tumors in mice. In addition, fluid taken specifically from people with mesothelioma seemed to prevent chemotherapy medications from killing cancerous cells.
Fluid from metastatic pleural cancer patients also brought on cell growth and migration. Even fluid from lungs without cancer had these effects on cells. However, both these fluids did not have an effect as potent as that taken from mesothelioma patients.
“This proof-of-concept study reveals potent biological capabilities of malignant pleural fluid in mesothelioma pathobiology,” the authors wrote in their report.
Overall, the results indicate that growth factors and other substances are present in mesothelioma fluid and can further complicate cancer. Future clinical efforts might be directed at neutralizing pleural effusion and its effects, rather than simply regarding it as a byproduct of cancer with no biological influence.