Scientists have identified versions of a gene that confer a 50% greater chance of developing estrogen-responsive tumors, Bloomberg reports. The study, published in Nature Genetics, found two common gene variants on chromosome 5 that correlated with higher incidences of the types of cancer that respond to estrogen levels. Genetic testing could indicate which women might benefit most from hormone-blocking therapy.
The affected genes have tiny variations in their DNA sequence that change the makeup of proteins responsible for killing undesirable cells. Three-fourths of breast cancers have estrogen-sensitive receptors on their surfaces, and increased rates of cancer have been linked to use of hormone therapy. Breast tumors are the second-most-common cancer in American women, with 182,000 cases each year.