Research Round-up

From the Summer 2017 edition of Vanderbilt Medicine Magazine

Studies find tonsillectomies offer only modest benefits

Removing tonsils modestly reduced throat infections in the short term in children with moderate obstructive sleep-disordered breathing or recurrent throat infections, according to a systematic review conducted by the Vanderbilt Evidence-based Practice Center for the Agency for Healthcare Research and Quality (AHRQ).

Four papers derived from the larger review include two that were published online on Jan. 17 and appeared in the February issues of

Pediatrics. These papers report results regarding the effectiveness of tonsillectomy for treating children with obstructive sleep-disordered breathing or recurrent throat infections. The papers concluded that more research is necessary to determine the long-term impacts of tonsillectomies in those groups.

In the full systematic review, Vanderbilt researchers considered almost 10,000 studies of tonsillectomy efficacy, primarily randomized control trials.

“It’s probably the most comprehensive study in tonsillectomy literature ever done,” said investigator David Francis, M.D., M.S., assistant professor of Otolaryngology. “We determined the lay of the land of what’s known and what’s not known about this extremely common procedure.”

 

Blood type linked to cancer survival

Ovarian cancer is the fifth leading cause of cancer deaths among women in the United States. Last year more than 14,000 deaths were reported. Despite treatment advances, overall five-year survival after diagnosis remains abysmally low at 45 percent.

ABO blood type has been linked to multiple diseases including pancreatic and ovarian cancer risk. Two small studies previously reported shorter survival rates among ovarian cancer cases with blood type A.

In the largest such study conducted to date, Alicia Beeghly-Fadiel, MPH, Ph.D., and colleagues found just the opposite. They reported in PLOS ONE that cases with type A blood were associated with significantly longer ovarian cancer survival.

Blood type antigens are expressed not only on red blood cells but also on epithelial and endothelial cells. Dysregulation of the enzyme encoded by the ABO gene could also affect cellular adhesion, cell membrane signaling, and the host immune response.

Further studies on blood type and ovarian cancer survival are warranted, the researchers concluded.

 

PET imaging to predict tumor response

About 10 percent of patients with colorectal cancer express a mutated form of the signaling molecule BRAF, which may be targeted for treatment by selective BRAF inhibitors. PET (positron emission tomography) imaging using a standard glucose probe is not able to predict response to BRAF inhibitors.

In addition to becoming dependent on glucose, cancer cells exhibit increased dependency on the amino acid glutamine. H. Charles Manning, Ph.D., and colleagues explored the use of a glutamine PET probe to predict response to mutant BRAF-targeted therapy in preclinical mouse models of colon cancer. They found that glutamine PET imaging predicted response to BRAF inhibition in tumors expressing mutant BRAF, but not in tumors expressing wild-type BRAF.

The findings, reported in the June issue of Molecular Imaging and Biology, demonstrate the utility of non-invasive PET imaging of glutamine uptake to predict response to BRAF-targeted therapy in colon cancer and could improve patient selection in colon cancer trials using BRAF-targeted therapies.