Posts Tagged ‘center’

Soy supplementation adversely effects expression of breast cancer-related genes

The impact of soy consumption on breast cancer prevention and treatment is not clear although many women believe soy supplementation is beneficial based primarily on results from epidemiological studies. Moshe Shike, M.D., from the Department of Medicine at Memorial Sloan-Kettering Cancer Center and Weill Cornell Medical College in New York, NY, and colleagues conducted a randomized placebo-controlled study of the effects of soy supplementation on gene expression and markers of breast cancer risk among women diagnosed with invasive breast cancer. The study, run between 2003 and 2007 at Memorial Sloan-Kettering, enrolled a total of 140 patients who were randomized to either soy supplementation (soy protein) or placebo (milk protein), which lasted from the initial surgical consultation to the day before surgery (range=7-30 days). Tumor tissues from the diagnostic biopsy (pre-treatment) and at the time of resection (post-treatment) were then analyzed. They observed changes in several genes that promote cell cycle progression and cell proliferation among women in the soy group.

The authors conclude, “These data raise concern that soy may exert a stimulating effect on breast cancer in a subset of women.”

In an accompanying editorial, V. Craig Jordan, O.B.E., D.Sc., Ph.D., FMedSci, from the Department of Oncology at the Georgetown University Lombardi Comprehensive Cancer Center, Washington, DC, discusses how timing of soy supplementation is critical and reviews the evidence in the literature on phytoestrogens, which are contained in soy, and their known action in breast cancer. He writes, the study by Shike et al. “…illustrates the dangers of phytoestrogen consumption too soon, around menopause, but the biology of estrogen in estrogen-deprived conditions suggests that phytoestrogen could have benefit a decade after menopause.” He cautions that appropriate doses of soy and timing of consumption are critical considerations.

source : http://www.sciencedaily.com/releases/2014/09/140904183725.htm

Statistical Approach for Calculating Environmental Influences in Genome-Wide Association Study (GWAS) Results

The approach fills a gap in current analyses. Complex diseases like cancer usually arise from complex interactions among genetic and environmental factors. When many such combinations are studied, identifying the relevant interactions versus those that reflect chance combinations among affected individuals becomes difficult. In this study, the investigators developed a novel approach for evaluating the relevance of interactions using a Bayesian hierarchal mixture framework. The approach is applicable for the study of interactions among genes or between genetic and environmental factors.

Chris Amos, PhD, senior author of the paper said, “These findings can be used to develop models that include only those interactions that are relevant to disease causation, allowing the researcher to remove false positive findings that plague modern research when many dozens of factors and their interactions are suggested to play a role in causing complex diseases.”

The model evaluates “gene by gene” and “gene by environment” factors by looking at specific DNA sequencing variations. Complex diseases are caused by multiple factors. In some cases a genetic predisposition or abnormality may be a factor. A person’s healthy lifestyle and environment, however, may help him or her overcome a genetic vulnerability and avoid a chronic disease like cancer. In other situations, a person whose DNA does not have an abnormality may develop one when exposed to known carcinogens like tobacco smoke or sunburn.

“Understanding the combinations of genetic and environmental factors that cause complex diseases is important,” said Amos, associate director of population sciences and deputy director of Norris Cotton Cancer Center, “because understanding the genetic architecture underlying complex disease may help us to identify specific targets for prevention or therapy upon which interventions may appropriately reduce the risk of cancer development or progression.”

The study applied the model in cutaneous melanoma and lung cancer genetic sequences using previously identified abnormalities (known as single nucleotide polymorphisms or SNPs) with environmental factors introduced as independent variables. The Bayesian mixture model was compared with the traditional logistic regression model. The hierarchal model successfully controlled the probability of false positive discovery and identified significant interactions. It also showed good performance on parameter estimation and variable selection. The model cannot be applied to a complete GWAS because if its reliance on other probability models (MCMC ). It is most effective when applied to a group of SNPs.

“The method was effective for the study of melanoma and lung cancer risk because these cancers develop from a complex interaction between genetic and environmental factors but understanding how these factors interact has been difficult to achieve without the sophisticated modeling that has been developed in this study,” said Amos.

source : http://www.sciencedaily.com/releases/2014/08/140827111811.htm

Provider, parental assumptions on teen sex yield ‘missed opportunities’ for HPV vaccine

Researchers at Boston University School of Medicine (BUSM) conducted hundreds of interviews to offer new insights into this frequent — and often controversial — clinic room conversation. Their findings and recommendations will appear in the September 2014 issue of Pediatrics.

Specifically researchers found that vaccination rates could be traced to personal biases and communication styles of providers. Providers who believed a child was at low risk for sexual activity — an assessment, they admitted, not always accurate — were more likely to delay administration. Often, this deferred decision was never readdressed. Those with high vaccination rates approached HPV vaccines as a routine part of the age 11 vaccine bundle, unequivocally recommended it to parents, and framed the conversation as one about cancer prevention.

“Emphasis on cancer prevention and concurrent administration with other routine childhood vaccines has the potential to dramatically reduce missed opportunities occurring among well- intentioned providers and parents,” explained lead author Rebecca Perkins, MD, MSc, assistant professor of Obstetrics and Gynecology at BUSM and a gynecologist at Boston Medical Center.

The researchers interviewed 124 parents and 37 health-care providers at four clinics between September 2012 and August 2013. Parents and providers were asked to discuss their reasons why their HPV vaccine eligible girls did or did not ultimately receive the vaccine. Remarkably, the most common parental reason (44 percent) was that their child was never offered the vaccine. Other common reasons included the perception that the vaccination was optional instead of recommended or being told by their provider that it was unnecessary prior to sexual debut. Among those that declined the vaccine, the rationale often involved safety concerns and a belief that their daughters were too young to need it.

source : http://www.sciencedaily.com/releases/2014/08/140818012326.htm