Israeli and American researchers announced this week a potential breakthrough in halting breast cancer metastasis, in mice. Whether the combination chemotherapy and genetic therapy works as well in humans remains to be seen.
The discovery was made by a joint team comprised of scientists from Tel Aviv University and Massachusetts Institute of Technology.
Dr Noam Shomron of Tel Aviv University’s Sackler School of Medicine, said: “We wanted to find a way to stop metastasis from happening altogether. It’s the turning point, where survival rates drop exponentially”. Metastasis is the spread of a cancer from one organ or part of the body to another without being directly connected with it.
The mission, Dr Shomron explains, is to stop a cancer cell’s ability to change shape and move, which is how metastasis happens: “Cancer cells alter their cytoskeleton structure in order to squeeze past other cells, enter blood vessels and ride along to their next stop: the lungs, the brain or other vital organs”.
Researchers began their work by investigating the range of cell mutations in a tumour and looked at sites within the genes that play regulatory roles. While studying the cells the researchers notice that mutations were involved in metastasis.
They also developed a naturally occurring RNA-based drug (RNAs are regulators of genes) to control cell movement, and created a safe nanovehicle with which to deliver the microRNA to the tumour site.
Two weeks after initiating cancer in the breasts of their lab mice, the researchers injected into primary tumour sites a hydrogel that contained naturally occurring RNAs to target the movement of cancer cells from primary to secondary sites. Two days after this treatment, the primary breast tumours were removed. The researchers discovered that the mice that had been treated with two different microRNAs had very few or no metastatic sites, whereas the control group – injected with random scrambled RNAs – exhibited a fatal proliferation of metastatic sites.
One in eight women worldwide are diagnosed with the disease every year, and the chance of dying from it, is about 1 in 36. Breast cancer is rarer in men, but if diagnosed they are more likely to die from it than women are; the five-year survival rate for women overall was 83%, compared to 74% for men.