Category Archives: Transhuman News

PUBLIC RELEASE DATE:

25-Nov-2014

Contact: Amy Blustein ablustein@wihri.org 401-681-2822 Women & Infants Hospital @womenandinfants

There has been much recent debate on the benefits and risks of screening for breast cancer using BRCA1 and BRCA2 mutations in the general adult population. With an estimated 235,000 new breast cancer diagnoses each year in the U.S. and more than 40,000 deaths, it is clearly important to be able to determine which women may be genetically predisposed to breast cancer.

Glenn E. Palomaki, PhD, associate director of the Division of Medical Screening and Special Testing in the Department of Pathology and Laboratory Medicine at Women & Infants Hospital of Rhode Island has recently published an invited commentary in the November issue of Genetics in Medicine. The commentary is entitled "Is it time for BRCA1/2 mutation screening in the general adult population? Impact of population characteristics."

A family history of breast or ovarian cancer or a personal history of early-onset cancer are strong risk factors for breast cancer. Systematic criteria when caring for a patient with a positive family history have been well established by such agencies as the U.S. Preventive Services Task Force and the National Comprehensive Cancer Network.

Dr. Palomaki said, "With the identification of the tumor suppressor genes BRCA1 and BRCA2 in the 1990s, the scientific community has extensively explored both the personal and population impact of carrying a deleterious mutation in these genes. Any new population-based screening test, such as testing for BRCA1 and BRCA2 mutations, requires consideration of key performance characteristics that evaluate both strengths and shortcomings before its introduction."

In his commentary, Dr. Palomaki cited two recent publications that present perspectives on routine, population-based screening for breast cancer using BRCA1/2 mutations in different populations.

"Together, these two publications offer an unusual opportunity to compare and contrast how distinct population differences, such as the mutations carrier rate, might influence the feasibility of population-based screening," said Dr. Palomaki. "Because founder mutations are more common in Ashkenazi Jewish women, are more easily identified and account for a higher proportion of all breast cancer cases, pilot trials in that population are indicated before launching widespread screening in Israel to identify and resolve implementation issues. Such screening in the United States, however, is more complicated, tilting the balance away from routine population screening, as least for the moment."

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Pathology specialist contributes to debate on breast cancer gene screening

PUBLIC RELEASE DATE:

24-Nov-2014

Contact: Vanessa Wasta wasta@jhmi.edu 410-614-2916 Johns Hopkins Medicine @HopkinsMedicine

After mining the genetic records of thousands of breast cancer patients, researchers from the Johns Hopkins Kimmel Cancer Center have identified a gene whose presence may explain why some breast cancers are resistant to tamoxifen, a widely used hormone treatment generally used after surgery, radiation and other chemotherapy.

The gene, called MACROD2, might also be useful in screening for some aggressive forms of breast cancers, and, someday, offering a new target for therapy, says Ben Ho Park, M.D., Ph.D., an associate professor of oncology in the Kimmel Cancer Center's Breast Cancer Program and a member of the research team.

The drug tamoxifen is used to treat estrogen receptor-positive breast cancers. Cells in this type of breast cancer produce protein receptors in their nuclei which bind to and grow in response to the hormone estrogen. Tamoxifen generally blocks the binding process of the estrogen-receptor, but some estrogen receptor-positive cancers are resistant or become resistant to tamoxifen therapy, finding ways to elude its effects. MACROD2 appears to code for a biological path to tamoxifen resistance by diverting the drug from its customary blocking process to a different way of latching onto breast cancer cell receptors, causing cancer cell growth rather than suppression, according to a report by Park and his colleagues published online Nov. 24 in the Proceedings of the National Academy of Sciences.

Specifically, the team's experiments found that when the gene is overexpressed in breast cancer cells--producing more of its protein product than normal--the cells become resistant to tamoxifen.

One piece of evidence for the gene's impact was demonstrated when the Johns Hopkins scientists blocked MACROD2's impact in breast cancer cell cultures by using an RNA molecule that binds to the gene to "silence," or turn off, the gene's expression. But the technique only partially restored the cells' sensitivity to tamoxifen.

To conduct the study, the scientists examined two well-known databases of breast cancer patients' genetic information, The Cancer Genome Atlas and the Molecular Taxonomy of Breast Cancer International Consortium study. Patients who had MACROD2 overexpressed in primary breast cancers at the original breast cancer site had significantly worse survival rates than those who did not, according to an analysis of the patient databases.

With this in mind, the Johns Hopkins scientists suggest that clinicians may be able to look at MACROD2 activity to help them identify aggressive breast cancers at early stages of growth.

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Johns Hopkins scientists link gene to tamoxifen-resistant breast cancers