Breast cancer has been prevented from spreading in mice with a simple cocktail of drugs, some of which are already approved for human use. The spread, or metastasis, of cancer is the most dreaded aspect of the disease: tumours formed this way are responsible for 90% of cancer deaths. But the process has been difficult to fathom — two tumours may by all appearances be identical, yet one will spread and one will not. And a tumour may shed hundreds or thousands of cells into the bloodstream every day, of which only a tiny fraction will successfully lodge in a new site and start to proliferate into a new cancer.
In 2005, Joan Massagué at the Memorial Sloan-Kettering Cancer Center in New York identified a roster of genes that seem to help breast cancer cells to metastasize to the lung. Now Massagué’s team has shown how four of these genes specifically work in concert to fuel metastasis. Addressing these four genes with drugs, they show in mice, has a dramatic effect.
Massagué hopes that this approach will work better than existing treatments, because it is targeted against genes now proven to fuel tumour growth and metastasis. And, he notes, two of the drugs are already in clinical use, which should speed clinical trials. “You couldn’t have it better,” he says. Other researchers say they would like to see data from human patients before getting too excited.