TUMOR SUPPRESSOR
Combination gene therapy reduces the number of nonsmall-cell-lung-cancer tumors by 75 percent in mice
Prostate-cancer treatment helps elderly
WASHINGTON
Elderly men with early prostate cancer live significantly longer if they receive treatment than those who adopt a wait-and-see approach, as commonly recommended. A study of 44,630 men age 65 to 80 years found that those who sought treatment for their prostate cancer with radiation or surgery had a 31-percent lower risk of death than those who waited. Even the oldest men between the ages of 75 and 80 benefited from treatment.
"Even though prostate cancer is commonly considered an indolent (slow to develop and painless) disease, this observational study suggests a reduced risk of mortality associated with active treatment for low- and intermediate-risk prostate cancer in the elderly," said the authors of the study published in the Journal of the American Medical Association.
Dr. Yu-Ning Wong of the Fox Chase Cancer Center in Philadelphia, who led the study, said that the findings challenge the commonly held notion that early prostate cancer in elderly patients evolves so slowly that there is no need to treat them as they will probably die of something else first.
"The treatment of prostate cancer in older men ... has been controversial because the concern about side effects is an important one," Wong said. "I think our study suggests there may be a benefit to treatment in this patient population but that of course needs to be weighed against other concerns."
He also acknowledged though that the study's design had limitations and the results would need to be confirmed by further research.
One in four US women has HPV
WASHINGTON
About a quarter of females in the United States aged 14 to 59 may have the sexually transmitted infection human papillomavirus (HPV), which is linked to cervical cancer, according to research by the Centers for Disease Control and Prevention (CDC).
"Our study provides the first national estimate of prevalent HPV infection among females aged 14 to 59 years in the United States," wrote the team of scientists led by Eileen Dunne in the Journal of the American Medical Association. "Our data indicate that the burden of prevalent HPV infection among women was higher than previous estimates."
HPV is the most commonly sexually transmitted infection in the US. The most virulent types can cause cervical, anal, and other genital cancers. HPV types 16 and 18 are responsible for about 70 percent of cervical cancers worldwide.
The study was based on DNA testing on 2,026 self-collected vaginal swabs among females aged 14 to 59 who took part in the 2003-2004 National Health and Nutrition Examination Survey. Nearly 27 percent of the samples tested positive for HPV DNA.
The principal risk factors cited by the scientists were age, marital status, and increasing numbers of sexual partners.
The study comes amid an uproar about an HPV vaccine developed by Merck that targets young teenaged girls. The Merck vaccine is effective against the four most common types of HPV and was approved by the US Food and Drug Administration in June 2006. The vaccine is aimed primarily at girls aged nine to 13 because, to be highly effective, it should be administered before the first sexual relations.
Experimental drug starves tumors
PARIS
An experimental cancer drug designed to cut off the blood supply that feeds tumors has shown promise in a small-scale trial on human volunteers. The drug blocks an enzyme involved in the processing of nitric oxide, a chemical that helps maintain the tumor's blood supply, thus enabling cancer cells to grow and divide.
Doctors in London recruited seven women and 11 men in the phase-I trial. Twelve had lung cancer, five prostate cancer, and one cervical cancer. In eight patients who were given higher doses of the drug, L-NNA, scans showed that the blood volume in their tumors dropped sharply an hour after treatment, a fall that was maintained 24 hours later. As for side effects, three patients suffered from hypertension and three had palpitations.
L-NNA stands for N-nitro-L-arginine, the enzyme that the blocker targets. The researchers, led by Quan-Sing Ng of the Mount Vernon Cancer Center, said the "exciting" results warrant putting L-NNA through further trials. The paper is published by Lancet Oncology.
Genes quash lung cancer in mice
CHICAGO
An experimental lung-cancer treatment that drastically suppresses tumors in mice may point the way to more effective and less toxic therapies for this type of cancer in humans, according to a study published in Cancer Research.
Texas researchers who administered two cancer-suppressing genes to mice reported that the combination gene therapy reduced the number of nonsmall-cell-lung-cancer tumors per mouse by 75 percent and the weight of tumors by 80 percent. "We saw significant tumor regression, with minimal side effects," said author Jack Roth, a professor at the University of Texas Anderson Cancer Center. "The low toxicity of this treatment suggests we should be able to give high doses of it."
The researchers said that the two genes, which are delivered to the tumors via nanoparticles, work synergistically to induce apoptosis. On its own, the gene p53 causes defective cells to commit suicide. It is often lacking or defective in cancer cells. FUS1 is a tumor suppressor lacking in most human cancers, but it also boosts the effect of p53 by inhibiting the release of a protein that degrades p53.
Doctors at the Anderson Cancer Center in Houston, Texas, are testing the FUS1 gene in patients with advanced nonsmall-cell lung cancer-the most common type of lung cancer. The researchers who conducted this study said this therapy could be a viable alternative to chemotherapy for aggressive lung cancers that have spread to other organs, because, unlike chemotherapy, it spares healthy cells, and in mice, at least, it has a better response rate.
In a separate study, researchers from Dartmouth Medical School said they may have identified a biomarker for a particularly deadly form of breast cancer. The biomarker, a protein called nestin, is present in abundance in basal epithelial tumors, a highly aggressive form of cancer that can be difficult to diagnose and manage. If a noninvasive test could be devised to detect nestin, the protein could be used to screen for women at risk for this type of cancer, which accounts for a disproportionate number of deaths.
FDA okays genetic test for breast cancer
WASHINGTON
The United States Food and Drug Administration (FDA) has approved a new genetic test of the likelihood of recurring breast cancer, five to 10 years after its onset. MammaPrint, made by the Dutch firm Agendia, has been available in Europe since 2005 and is based on recent molecular technology to predict the likelihood breast cancer can propagate to other tissues in the body, the FDA said.
The recurrence of cancer is partly dependent on the activation and suppression of certain genes located in the tumor. MammaPrint measures the activity of these genes to help physicians understand their patients' odds of the cancer spreading.
Agendia compared the genetic profiles of a large number of breast-cancer patients and identified a set of 70 genes whose activity confers information about the likelihood of tumor recurrence and metastasis.
MammaPrint uses customized DNA microarrays, each of which contains three identical sets of the 70 genes to be analyzed. This enables three independent measurements of the 70-gene profile, increasing confidence in the test result. A DNA microarray is a collection of tens of thousands of genes, printed onto a glass slide. Each spot on the slide contains a unique DNA fragment with a known sequence.
In addition, the customized arrays contain several hundred carefully selected normalization genes. Also, negative control genes are present on each microarray; these are DNA sequences to which no human mRNA can bind and are used to monitor various technical aspects of the microarray process.
Gum disease, high sugar linked to pancreatic cancer
WASHINGTON
Gum disease may increase the risk of the highly fatal cancer of the pancreas, according to a study in the Journal of the American Medical Association.
"Our study provides the first strong evidence that periodontal disease may increase the risk of pancreatic cancer," said lead author Dominique Michaud, professor at the Harvard School of Public Health. "This finding is of significance as it may provide some new insights into the mechanism of this highly fatal disease," he said.
Periodontal disease is caused by bacterial infection or inflammation of the gums that over time causes loss of bone that supports the teeth. Two previous studies established a link between tooth loss caused by severe gum disease (periodontitis) and pancreatic cancer, but one involved only smokers and the other was not conclusive because it did not "control" for smoking in the analysis.
The data for this new study were collected from 1986 to 2002 and included 51,529 men working in US health professions. Researchers found 67 cases of gum disease among 216 cases of pancreatic cancer in the group.
One possible explanation for the results is that inflammation from gum disease may somehow cause the cancer, said Michaud. Another is that individuals with periodontal disease have higher levels of oral bacteria or nitrosamines-a carcinogen found in beer, fish, and pickled foods-in their mouths, and it may play a role in the cancer.
A Swedish study earlier linked heavy consumption of sugary drinks and food to increased risk of developing pancreatic cancer. The Karolinska Institute study, published in the American Journal of Clinical Nutrition, surveyed 80,000 men and women in good health whose food habits were observed between 1997 and 2005. A total of 131 in the group developed pancreatic cancer.
"Scientists have now, for the first time, shown that the consumption of sweetened food and drink affects a person's chances of developing pancreatic cancer," the institute said.
The researchers said most at risk were those who drank high quantities of fizzy or syrup-based drinks. The group who said they drank such products twice a day or more ran a 90-percent higher risk than those who never drank them. People who added sugar to food or drinks at least five times a day ran a 70-percent greater risk than those who did not, the study showed.
Pancreatic cancer "is possibly caused when the pancreas produces heightened levels of insulin as a consequence of upset glucose metabolism," the researchers said, adding that eating a lot of sugar is a common way of increasing insulin production.
Gene variant protects v. breast cancer
PARIS
Doctors have long known that certain variations of genes boost the risk of breast cancer, but a new study says there is also a gene variant that offers modest protection against the disease.
Women with a particular form of the CASP8 gene run a roughly 10-percent lower risk of breast cancer compared with counterparts without this variant, according to the study published in Nature Genetics. CASP8 is found in around one in eight of women of European descent, according to the Breast Cancer Association Consortium. Two genes that are commonly associated with breast cancer are variants of BRCA1 and BRCA1.
Cancer of the breast has been dubbed "the silent killer" for the many lives it claims, because the disease is often detected only at its late stages. Two genes that are commonly associated with breast cancer are variants of BRCA1 and BRCA1, together accounting for less than 25 percent of inherited risk of this disease. M
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