MicroRNA Acts As Genetic Switch For Breast Cancer Spread

Queensland scientists have identified a genetic “switch” that indicates whether a woman’s breast cancer will spread.

AsianScientist (Nov. 19, 2013) – Queensland scientists have identified a genetic “switch” that indicates whether a woman’s breast cancer will spread.

Teams from QIMR Berghofer Medical Research Institute and the Institute of Molecular Bioscience (UQ) have found that a particular RNA (ribonucleic acid) molecule goes missing in aggressive cancers.

QIMR Berghofer’s Dr. Nicole Cloonan said the finding could provide a clearer prognosis for breast cancer patients, and ultimately open the door for new treatments.

“Essentially, this particular gene fragment, or microRNA, normally acts like an emergency brake in our genetic program, ensuring our cells continue to reproduce normally,” Dr. Cloonan said. “But we’ve identified that this “emergency brake” fails in invasive, aggressive tumors.”

Its sudden absence in cancer tests would be a clear marker that a tumor is likely to spread.

“And we know that primary breast cancer rarely kills; it is those aggressive tumors that spread, or metastasize, which result in poor outcomes,” Dr Cloonan said.

Breast cancer is the most common cancer in women. Survival can depend on when the cancer is diagnosed; once it has metastasized there is a five-year survival rate of only 21 percent.

According to Cloonan, the pathway that the microRNA acts on seems to be a common cellular process as same microRNA also goes missing in aggressive liver, stomach, brain and skin cancers. This could potentially make the microRNA a new drug target for the treatment of aggressive cancers, she said.

“These microRNAs were once thought the “junk” of our genetic programs, something that fine-tuned pathways but that was all. But in recent years, we’ve come to appreciate the driving role they play in cancer, and as this work shows, a key role in preventing breast cancer cells from migrating throughout a person’s body.”

The article can be found at: Cloonan N et al. (2013) miR-139-5p is a regulator of metastatic pathways in breast cancer.


Source: QIMR; Photo: USAG-Humphreys/Flickr/CC.
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