Recent studies have suggested that breast cancer can be classified as up to 10 different diseases. A new study published online in Nature sought to determine the various genetic drivers of these diseases, says the Broad Institute. Researchers there and at the National Institute of Genomic Medicine in Mexico City, Beth Israel Deaconess Medical Center, and Dana-Farber Cancer Institute sequenced the whole exomes of breast tumors and normal DNA from 103 patients as well as the entire genomes of 22 patients' normal and cancer tissues. From studing the frequency of the various mutations present in tumor samples, the researchers found novel gene alterations that had never been associated with breast cancer before, the Broad says.
One of the new alterations discovered — a recurrent fusion of the genes MAGI3 and AKT3 — was found in aggressive triple-negative breast tumors. These tumors are normally untreatable with conventional therapy, but new drugs are being developed to target the MAGI3-AKT3 reshuffling, the Broad adds. The researchers also found recurrent mutations in the CBFB gene and deletions in RUNX1 — alterations that are normally found in blood cancers, the Broad says, but have never been detected in a solid tumor before.