http://www.digitaljournal.com/article/248631

Missing MicroRNA is Key to Breast Cancer Spread

Posted Jan 10, 2008 by ashley.woods4
US researchers announced on Wednesday that by restoring missing genetic material from breast tumors in mice they were able to stop the spread of the tumors.
This finding will allow doctors to make better treatment decisions of breast tumors and may lead to new ways to halt the spread of cancer.
"What's most important to us as cancer doctors is the concern that the cancer is going to come back," said Tavazoie, whose study appears in the journal Nature.
Cancer spreads when small pieces break off the main tumor and attack other organs, the process is called metastasis. The new research will help doctors determine if a particular tumor has the potential to spread. If a particular tumor does have the potential to spread, doctors can now develop new therapies to stop the spread of the tumor.
Tavazoie has been doing all his research in the lab of Joan Massague, a Howard Hughes Medical Institute researcher. They are set out to isolate the process that causes aggressive tumors to spread.
The two found tiny bits of RNA, known as microRNA, that suppress the spread of breast tumors to the lungs and bone. When they put the bits of microRNA back into the breast tumors in mice the tumors lost the ability to spread.
"We think these microRNAs will help us to know if this is an aggressive tumor or not," Tavazoie said in a telephone interview.
Tavazoie goes on to say that if they are able to determine the cancer is aggressive they will be able to treat it properly. This research may also allow some women with less aggressive breast tumors to be able to skip chemotherapy altogether.
Tavazoie's team also found a strong association between the loss of miR-335 and cancer relapse when they researched which genes were causing the trouble when the microRNAs went missing.
When this microRNA was absent, they found strong activity in a set of six genes. SOX4 and TNC, two of the six genes, were already known to play a role in cell migration. When Tavazoie's team suppressed the activity of the genes they were able to reduce the cancer's ability to spread.