Specific H. pylori Strains Are Associated with Precancerous Lesions
A new study suggests that previous estimates of the risk of gastric cancer following infection with the bacterium Helicobacter pylori may be too low. The research identifies certain strains of the bacterium associated with precancerous gastric lesions.
H. pylori live in the human stomach. But many people with H. pylori infections never develop gastric cancer. Some evidence suggests that genetic variation among different strains of the bacteria may explain why some infections result in gastric cancer while others do not.
Martyn Plummer of the International Agency for Research on Cancer in Lyon, France, and colleagues examined the relationship between several strains of H. pylori and the development of gastric cancer. They analyzed gastric biopsy specimens from 2,145 participants in a chemoprevention trial in Venezuela.
The researchers found a strong association between precancerous gastric lesions and infection with particular strains of H. pylori. "Our study adds to the emerging body of evidence that the strength of the association between H. pylori and gastric [cancer] has been underestimated. In a recent review of infection-related cancer, the proportion of all gastric cancers worldwide attributed to H. pylori was estimated to be 63%. Our results imply that, in populations with a high prevalence of [disease-causing] H. pylori, the attributable fraction may be even higher," the authors write.
Contact: Martyn Plummer, firstname.lastname@example.org, + 33 472728446
Gene May Hinder Spread of Prostate Cancer
Researchers have identified a gene, known as OGR1, that suppresses prostate cancer metastasis in mice.
Cancer deaths are largely attributed to tumor metastasis--when the cancer cells spread to other parts of the body--rather than primary tumors. Previous research has shown that OGR1 is expressed at lower levels in metastases than in primary prostate tumors.
Lisam Shanjukumar Singh, Ph.D., of Indiana University in Indianapolis and colleagues showed that prostate cancer cells that overexpress OGR1 formed fewer metastases in mice and migrated more slowly in laboratory tests.
"Our results show that OGR1 suppresses prostate cancer metastasis without affecting the primary tumor progression, suggesting that OGR1 is a novel metastasis suppressor gene for prostate cancer," the authors write.
Contact: Yan Xu, Indiana University, email@example.com, (317) 274-3972
Genes and Drug Dose Predict Increased Risk of Neutropenia from Irinotecan
Patients with a particular version of the UGT1A1 gene are at greater risk of neutropenia, a shortage of certain white blood cells, if they are taking medium or high doses of the anticancer drug irinotecan. In 2005, the FDA highlighted an increased risk of neutropenia from irinotecan in these patients. However, it is unclear when DNA testing would be of highest value for managing this important anticancer drug.
Janelle Hoskins, Ph.D., of the University of North Carolina in Chapel Hill and colleagues reviewed data from nine studies on irinotecan and neutropenia risk according to which version of UGT1A1 patients had. They found that patients who received a medium or high dose of the drug had greater risk of neutropenia if they had two copies of UGT1A1*28, compared with two copies of UGT1A1*1 or one of each. At lower doses the risk was the same regardless of which version patients had.
"We recommend that the product information for irinotecan be amended to describe the association between irinotecan dose and risk of [neutropenia] among patients with a UGT1A1*28/*28 genotype," the authors write.
Contact: David Etchison, director of communications, University of North Carolina School of Pharmacy, (919) 966-7744
Also in August 28 JNCI:
eurekalert. org/ emb_releases/ 2007-08/ jotn-pc082307. php
eurekalert. org/ emb_releases/ 2007-08/ jotn-rp082307. php
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