New genomic test identifies all breast cancer types

Salt Lake City, February 11: The researchers have discovered ‘a set of 50 genes’ that helps identifying the four types of breast cancerdefine.

According to a research conducted at Washington University School of Medicine in St. Louis and collaborating institutions, the set of 50 genesdefine will help doctors predict the most effective therapy for each breast cancerdefine type and enable best-personalized treatment for all patients.

"Unlike a widely used genomic test that applies only to lymph-node negative, estrogen-receptor positive breast cancer, this new genomic test is broadly applicable for all women diagnosed with breast cancer," says breast cancer specialist Matthew Ellis, M.D., Ph.D., a member of the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University.

Breast cancer is the result of genetic abnormalities in breast tissue but some breast cancers do not have identical genetic alterations. Ellis and his colleagues analyzed the gene activity of more than 1,000 breast tumors. The researchers listed down a set of 50 genes that could identify each type of previously defined tumor known as luminal A, luminal B, HER2-enriched and basal-like. As opposed to it, OncotypeDX, a commonly used genomic test does not identify all four tumor types.

The researchers also compared the activity of the 50-gene set to see how well 133 breast cancer patients responded to standard chemotherapy. They found that their genetic test was highly sensitive and predictive for chemotherapy response.

They found that basal-like breast cancer was the most sensitive to the chemotherapy and luminal B the least. And luminal A was not found sensitive at all to chemotherapy.

"Luminal B tumors are a very poor prognosisdefine group, and none of the current conventional therapies are particularly effective against it," Ellis says. "The ability to identify luminal B tumors accurately makes it possible to develop better therapies for this type."

The study co-author, Dr. Philip Bernard of the University of Utah's Huntsman Cancer Institute said, "Our research shows that there is a subset of women who can be cured without getting any treatment at all, other than a lumpectomydefine; In women whose tumors have spread, we can predict with very high accuracy which women are going to respond to chemotherapy and which type of chemotherapy will work -- if chemo isn't going to be beneficial, we shouldn't be giving it."

The study is published in the Journal of Clinical Oncology.