Houston: In a major breakthrough, which can dramatically increase survival chances of ovarian cancer patients, an Indian American scientist has identified two proteins whose presence increases the median survival rate by 11 years in patients with the disease.
A study of nearly 250 ovarian cancer patients by Dr Anil Sood, MD, professor in the departments of Gynecologic Oncology and Cancer Biology at M D Anderson, along with other researchers, found that woman with high levels of two proteins named Dicer and Drosha in their tumor cells had a median survival rate of 11 years. While, in patients with low levels of one or both proteins about 40% of those studied had a median survival of less than three years.
Sood’s discovery marks a significant advance for an emerging area of basic science called RNA interference, which one day may transform medicine.
“What’s important is that Dicer and Drosha are critical to the process of RNA interference,” Anil Sood said.
“RNA interference has only been known for about a decade. The components of the machinery, what it does in cancer, and how it affects outcomes and therapy are not fully known,” Sood said.
Potential clinical applications include using levels of the proteins as prognostic indicators to guide treatment decisions and eventually to exploit RNA interference to attack tumors, Sood said.
Interfering with gene expression the team measured expression levels of Dicer and Drosha in 111 invasive ovarian cancer tumors and then compared the results to the patients’ clinical outcomes.
The initial findings were supported by a second analysis of gene expression in a different group of 132 ovarian cancer patients.
Analysis of 91 patients with lung cancer and 129 breast cancer patients reached similar conclusions, however, only Dicer levels were found to affect survival. The mechanism has powerful therapeutic potential, because it affords scientists a new biological lever with which to stop genes from producing proteins inside cells. This is critical, because the cause of many diseases can be traced to the errant production of those proteins.
As part of the new study, Sood and his colleagues found that Dicer and Drosha play a critical part in the body’s RNA interference processes and that they appear to help suppress tumors.
Low levels of the proteins likely permit genes to continue functioning when they should be silenced.
The study findings help scientists better understand the biological details of the RNA interference process. By understanding this, they can better tailor drugs to impair the ability of tumor cells to multiply.
The researchers are working with M D Anderson and anticipate beginning clinical trials of those drugs within a few years.