A team from the Memorial Sloan-Kettering Cancer Center says the genetic "signature" may help predict how serious the disease may be.
In the journal Nature, they add the findings may help doctors offer more accurate prognosis to cancer patients and site a new target for breast cancer treatment.
Researchers were able to trace the gene by injecting mice with cancer cells from a patient with an aggressive breast tumor, which had spread. They watched to see which cells migrated to the animals' lungs and analyzed the genetic make-up of those cells.
Mice were used so scientists could follow the biological process which makes a breast tumor metastasize to the lung. Scientists identified a "thumbprint" of genetic activity, which involves 54 genes that appear to be associated specifically with lung metastasis.
Some genes functioned more vigorously than usual, while the activity of others was suppressed. This same genetic pattern was found in a group of 82 early stage breast tumors removed from patients.
Over half of the patients with the "thumbprint" went on to develop lung metastases, compared with only 10% whose primary tumors did not carry the gene set.
Lead researcher Dr. John Massague, said if a drug could successfully target these genes, the growth of tumor cells that could potentially spread to the lungs may be partially, if not completely, blocked.
Knowing which organ the cancer could return to would allow doctors to keep watch for early signs of the cancer's return.
Researchers will now look at more patients with breast cancer and see if a larger study confirms their findings and search for these patterns in other forms of cancer, which often spread to the lungs
