Researchers from the Memorial Sloan-Kettering Cancer Center in New York managed to identify four genes that seem to help breast cancer cells to metastasize to the lungs. This finding enabled them to prevent spreading of the breast cancer in mice with a cocktail of drugs already used in humans.

The identified genes are responsible for aggressive growth of the primary tumor and for metastasis as they help to hijack a network of blood vessels to nourish the tumor's own growth, help tumor cells escape into these same blood vessels to reach the lung, and help them to weasel their way through the capillary wall and grow.

The researchers show that addressing these four genes, EREG, MMP1, MMP2 and COX2, may have a major effect.

The researchers silenced the four genes in a line of human breast cancer cells and injected them into mice. The gene silencing halted the growth of breast tumors in the mice, and almost completely blocked the formation of lung metastases. The researchers showed that a combination of existing drugs known to inhibit the genes' action -- two approved drugs called cetuximab and celecoxib, plus an experimental one called GM6001 --had a similar effect to silencing the genes.

The scientists are now planning to find women whose breast tumors are relying on these four genes and test whether this combination of drugs would help to protect them from lung cancer. They are hoping that this approach will work better than existing treatments as it is targeting genes proven to fuel tumor growth and metastasis.