June 30, 2011

Breast cancer added to VICC gene test arsenal

Breast cancer added to VICC gene test arsenal

Carlos Arteaga, M.D.

Carlos Arteaga, M.D.

Vanderbilt-Ingram Cancer Center

Information from genetic tests in the tumors will be used to match patients to the best cancer therapies available, including drugs that are in early clinical trial testing.

Tumor mutation testing for breast cancer is the newest addition to VICC’s Personalized Cancer Medicine Initiative (PCMI), which was unveiled in the summer of 2010.

The PCMI program started with routine mutation screening for all lung cancer and melanoma patients, with plans to include other forms of cancer as new scientific information and targeted therapies become available.

Research spearheaded by Carlos Arteaga, M.D., professor of Medicine and Cancer Biology and director of the Vanderbilt Breast Cancer Program, led to the new breast cancer testing initiative.

“We are screening for a PI3 kinase mutation panel, which includes multiple mutations within a number of genes in the PI3 kinase cancer survival pathway,” explained Arteaga.

When these mutations are present in the tumor they super-activate the PI3K pathway, making it easier for the cancer to withstand standard therapies, grow and then spread.

Molecular alterations in the PI3K pathway occur in more than 30 percent of breast cancers and these mutations are more common in tumors that are positive for estrogen receptors (ER) or HER2.

Early trials suggest that tumors with mutations in this pathway might be particularly sensitive to drugs that inhibit PI3K, which are now in clinical development.

Arteaga and investigators in his VICC research laboratory have been exploring the significance of the PI3K pathway for several years.

“Early studies suggest that when PI3K mutations are present in tumors that are ER positive or HER2 positive, those tumors are resistant to hormonal therapies and anti-HER2 therapies, respectively.

“In addition to the current standard therapy for ER positive and HER2 positive cancers, patients with the PI3K mutations may need additional drugs that inhibit this pathway, and those drugs are now in development,” said Arteaga who is also the Donna S. Hall Professor in Breast Cancer Research at VICC.

VICC is participating in several clinical trials for drugs that block the PI3K pathway.

Ingrid Mayer, M.D., assistant professor of Medicine, and research fellow Justin Balko, Ph.D., Pharm.D., also were involved in the implementation of the new breast cancer testing program.

William Pao, M.D., Ph.D.

William Pao, M.D., Ph.D.

“The addition of mutation testing for a third form of cancer highlights Vanderbilt’s role at the forefront of personalized medicine,” said Pao.

“Some of the newest clinical research trials for promising new breast cancer drugs require knowledge of the patient’s PI3K status, so offering this test will allow us to add more patients to those clinical trials and provide them access to potential beneficial treatments.”

The mutation tests are performed in the VUMC Molecular Genetics Laboratory, led by Cindy Vnencak-Jones, Ph.D.

The latest information about the significance of PI3K mutations in breast cancer has been added to Vanderbilt’s MyCancerGenome website, under the supervision of Mia Levy, M.D., Ph.D., assistant professor of Biomedical Informatics.

The material found at www.mycancergenome.org is designed to help physicians and patients access important research studies about gene mutations involved in several types of cancer.

Other members of the VICC team involved in the new breast cancer testing program include Zengliu Su, M.D., Ph.D., Darson Lai, M.S., Ashley Lamb, PCMI program coordinator and Kimberly Dahlman, Ph.D., research instructor in Cancer Biology.