Tiny RNA Molecules Control Breast Cancer's Spread

ByABC News
March 24, 2008, 2:35 AM

Mar. 23 -- WEDNESDAY, Jan. 9 (HealthDay News) -- Researchers have zeroed in on a handful of tiny ribonucleic acid (RNA) molecules that seem to control whether or not breast cancer travels to the lung and bone.

These "microRNAs" essentially serve as brakes on the proliferation of cancer. When they are missing, that allows the disease to spread freely. When they are restored, however, the cancer cells lose some of their ability to metastasize, the Memorial Sloan-Kettering Cancer Center scientists report.

The work has implications both for predicting which cancers are aggressive and establishing new targets for drug therapy down the line.

"It's very interesting early research and may avail one day to discovering agents to suppress the growth of metastases," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. "It's very fine research."

The findings could also help individualize cancer therapies.

"One of the fundamental lessons which should be reinforced from this study is that breast cancer is not one disease. It is clearly a family of diseases and identifying mechanisms that turn on or turn off genes in one cancer helps us with what I would call class prediction," added Dr. Patrick Borgen, director of the Brooklyn Breast Cancer Project at Maimonides Cancer Center in New York City. "This is important, because it gives us another box to classify breast cancers in. The primary reason that more progress has not been made is that we've used a one-size-fits-all treatment paradigm for breast cancer."

"Researchers have opened up a whole new window on ways to look at subsetting breast cancers. That holds short-term possibilities to go back and look for a predictor of prognosis or predictor of response to therapy based on these small RNA molecules. That really is a very tangible short-term goal," Borgen added. "That, in and of itself, would be exciting enough, but unlike most prognostic factors that we identify, this is one [that] represents a potential target for intervention. I think this is really exciting. I think this is the real deal."