Posts Tagged ‘genetics’

New genetic risk markers in pancreatic cancer

The markers are variations in the inherited DNA code at particular locations along chromosomes. Several of these variations in the DNA code were identified that influence an individual’s risk for pancreatic cancer.

The discovery of these markers — along with four that were previously identified is important for several reasons, said Brian Wolpin, MD, MPH, first author of the report published online by Nature Genetics. One is that further study of these DNA variants may help explain on the molecular level why some people are more or less susceptible to pancreatic cancer than the average person. A second is the potential to identify people at increased risk who then might be candidates to undergo MRI or ultrasound scanning to look for early, treatable pancreatic tumors.

“Currently there is no population screening program for pancreatic cancer, which in 80 percent of cases is discovered when it’s too late to allow curative surgery — the cancer has already spread,” said Wolpin.

The only healthy individuals currently screened for pancreatic cancer are members of high risk families due to multiple family members with pancreatic cancer. “But the field has been struggling to find factors that can identify people at highest risk in the general population, when a strong family history is not present,” Wolpin said.

The study findings represent analyses of DNA from 7,683 patients with pancreatic cancer and 14,397 control patients without this cancer, all of European descent, from the United States, Europe, Canada, and Australia. The scientists used sequencing technology to examine more than 700,000 sites of the genome known to have single nucleotide polymorphisms (SNPs) — differing versions of a single letter of DNA code. These variations can alter the expression of a gene or the content of its message, and the researchers looked for variants that were associated with the risk of having pancreatic cancer. Research of this type is called a genome-wide association study, or GWAS.

Wolpin said the results confirmed the presence of four risk-associated SNPs that had been identified in a previous, smaller GWAS study. In addition, five new risk markers were discovered and a sixth that was of borderline statistical significance.

The risks linked to each SNP or marker were largely independent and additive, so that they may have utility in future attempts to identify individuals in the general population at higher risk for pancreatic cancer. The average lifetime risk of pancreatic cancer is 1.5 percent.

The long-term goal is to create a “risk stratification tool” that could be used in primary care practice to identify individuals who should undergo screening for pancreatic cancer with tests such as ultrasound or MRI.

The report includes authors from around the world, and includes several senior authors, one of whom is Charles Fuchs, MD, MPH, of Dana-Farber.

The project, known as PanScan III, was funded by numerous sources, including the National Cancer Institute of the National Institutes of Health under contract number HHSN261200800001E and the Lustgarten Foundation.

source : http://www.sciencedaily.com/releases/2014/08/140803193131.htm

Variations in key gene predict cancer patients’ risk for radiation-induced toxicity — ScienceDaily


The current results are based on a genome-wide association study, a type of study in which researchers examine numerous genetic variants to see if any of them are associated with a certain type of complication, which could sometimes emerge years after treatment was completed.

“Our findings, which were replicated in two additional patient groups, represent a significant step towards developing personalized treatment plans for prostate cancer patients,” said Barry S. Rosenstein, PhD, Professor, Radiation Oncology, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, the lead Mount Sinai investigator on the study. “Within five years, through the use of a predictive genomic test that will be created using the data obtained in the recent study, it may be possible to optimize treatment for a large number of cancer patients.”

For the study, Dr. Rosenstein and his team obtained blood samples from nearly 400 patients who were receiving radiotherapy treatment for prostate cancer. The blood samples were screened for roughly one million genetic markers, and each patient was monitored for at least two years to track incidents of side effects from the radiation. Data analysis showed which genetic markers were consistently associated with the development of complications following radiotherapy.




“The next step is to validate the results, and see if the same markers predict similar outcomes in patients with other forms of cancer,” said Dr. Rosenstein. Using the genomic test being developed, treatment plans can be adjusted to minimize adverse effects thereby allowing for an improved quality life for many cancer survivors.

source : http://www.sciencedaily.com/releases/2014/07/140708121730.htm