Until now, doctors have had difficulty determining which mesothelioma patients were the best candidates to receive the full array of anti-cancer treatments including surgery, chemotherapy and radiation. But new research may give doctors one more tool for identifying those patients.

Researchers from the United States and Israel have identified an RNA molecule found in cancerous tissue that may be useful in predicting a mesothelioma patient’s chances for survival after surgery.

Malignant mesothelioma is a relatively rare cancer of the lining of the lung or abdomen associated with asbestos exposure. Between 2,000 and 3,000 new cases are diagnosed in the U.S. each year.

In an article published this month in the medical journal Cancer Research, a team of researchers, based at New York University, the University of Hawaii and Rosetta Genomics Ltd., in Israel, said the presence of even a single specific microRNA has significant predictive value for assessing the course that a mesothelioma patient’s disease will take.

The research, if validated by follow-up studies, may give doctors a potent new clinical method for treating mesothelioma patients.

All people and other living organisms contain DNA and RNA, the building blocks of life. Each DNA molecule contains hundreds of millions of atoms in a unique sequence that carries the genetic information to construct and maintain cells. RNA translates the genetic information into specific instructions.

MicroRNAs are single stranded molecules that regulate gene expression. They play a major role in the progression of changes on a cellular and genetic level that reprogram a cell to undergo uncontrolled cell division, causing cancerous tumors.

MicroRNAs have been used as prognostic markers for numerous forms of cancer, including ovarian, pancreatic, lung and breast cancers. They’ve also been used as biomarkers to pinpoint the tissue where cancer originated. But few studies have explored the role of microRNAs in malignant pleural mesothelioma.

In two groups of patients, the researchers said the microRNA -- known as has-miR-29c --proved to be a reliable indicator of when the disease would worsen after surgery and the length of survival after surgery. The research was done on 129 samples of malignant mesothelioma tissue collected from 1990 to 2005.

With each tissue sample, the researchers had information about the mesothelioma patient including age, sex, stage of cancer, when the disease worsened after surgery and the time of death after surgery.

Using microRNA as a guide, the researchers were able to divide patients who had undergone surgery to remove tumors into two groups: those that would survive more than a year after surgery and those that died within12 months or less. Elevated amounts of microRNA were associated with significantly decreased spread of cancer cells and with prolonged survival, the researchers said.

In one group, for example, the researchers found that the presence of certain levels of has-miR-29c could be used to divide patients into a good prognosis group with median survival of 21 months and a poor prognosis group with median survival of nine months.

The research suggests that selected microRNA functions as an important control mechanism in malignant pleural mesothelioma. The researchers said further validation of the findings and follow-up research may provide insight for prognosis of mesothelioma in patients' potential therapies in the future.

The research was supported in part by philanthropic grants from the law firm of Belluck & Fox, LLP in New York and the Stephen Banner Lung Cancer Foundation.

Full article-
hsa-miR-29c* Is Linked to the Prognosis of Malignant Pleural Mesothelioma