THURSDAY, Jan. 1 (HealthDay News) -- In a finding that could help doctors fine-tune breast cancer treatments even further, a new study confirms that there are genes that increase the likelihood that the disease will spread throughout a woman's body.

Scientists from the National Cancer Institute (NCI), building upon earlier research, found in both mice and human breast tumor samples that a certain gene signature predicted the chance of metastasis. Many experts have believed that metastasis is primarily the result of non-inherited mutations in cancerous tissue.

"Our earlier studies clearly established that inherited factors also play an important role in metastatic progression and can help distinguish which tumors have a propensity to metastasize," study author Kent W. Hunter, head of the NCI's Metastasis Susceptibility Section in the Laboratory of Cancer Biology and Genetics, said in an NCI release. "Hopefully, in the future, we will be able to determine which women are more likely to have a tumor that would metastasize, and we could then tailor therapy specifically for them, avoiding the use of harsh treatments for those with a low probability of metastasis."

The researchers first discovered a gene signature in mice that raised the risk of breast cancer metastasis in mice by 20-fold. They then found the corresponding human gene signature, and it predicted relapse or recurrence in four of five breast cancer patients.

"Our study provides additional evidence of the role of inherited genes in human breast cancer progression," Hunter said.

The study was published in the Jan. 1 issue of Cancer Research.

More information

For more on breast cancer metastasis, go to the University of Michigan Comprehensive Cancer Center.

TUESDAY, Dec. 30 (HealthDay News) -- In another blow to the supposed cancer-fighting powers of vitamins C and E, new research suggests that supplement forms of the vitamins don't prevent the disease in women.

And another widely touted supplement, beta carotene, didn't help either, the new study found.

"Simply taking antioxidant supplements is insufficient to prevent cancer development," said study lead author Jennifer Lin, an assistant professor of medicine at Harvard Medical School.

But it's still a good idea to eat plenty of fruits and vegetables that are rich in nutrients such as antioxidants, Lin said.

Vitamin supplements have taken hits in a number of studies in recent years, with some research suggesting that supplements such as vitamins B, C, D, E, folic acid and calcium don't prevent cancer when taken in combinations or alone. The findings contradict other studies that had suggested the vitamins may have a protective effect due to antioxidants, which reduce damage to cells in the body.

For the new study, the researchers looked at a group of 8,171 women who were randomly assigned to take a supplement, a combination of supplements or a placebo. The supplements were vitamin C (500 milligrams a day), vitamin E (600 International Units every other day) and beta carotene (50 milligrams every other day).

The women, all over the age of 40, took part in the study from 1995 and 1996 until 2005, for an average of nine years. They all had cardiovascular disease or were at risk for it.

A total of 624 of the women developed cancer, and 176 died from it during the period of the study. The researchers didn't find any "statistically significant" evidence that the supplements either helped or hurt a woman's risk of developing cancer.

The findings were published online Dec. 30 in the Journal of the National Cancer Institute.

Why didn't the supplements prevent cancer, as some earlier research had suggested? One theory, Lin said, is that they might be effective in people who are poorly nourished, but not in well-nourished people such as the women in the study. She said some research has shown that diets lacking in antioxidants -- found in fruits and vegetables -- can lead to higher cancer rates.

The study isn't the final word, Lin said. "More studies need to be done to see who may benefit from antioxidant supplements. One trial study has suggested that men, compared with women, were more likely to gain benefits from supplementation with antioxidants in reducing cancer risk. However, such findings need verification."

Dr. Demetrius Albanes, senior investigator with the U.S. National Cancer Institute, who wrote a commentary accompanying the study, acknowledged that while the study results were disappointing, it's possible that the supplements could have had positive effects in women who weren't at high risk for cardiovascular disease, as were those in the study.

He added that the study indicated that vitamin E may have some benefit at preventing colon cancer specifically, as other research has suggested.

In the big picture, Albanes said, research shows that lower-calorie diets with plenty of fruits and vegetables do have benefits. "But right now, the issue of vitamin supplementation is still very much up in the air for men and for women," he added.

More information

Learn more about the links between diet, exercise and cancer risk from the American Cancer Society.

MONDAY, Dec. 29 (HealthDay News) -- A diet rich in the inorganic phosphates found in many natural and processed foods accelerated the growth of lung cancers in rats, South Korean researchers report.

"Our study suggests that dietary regulation of inorganic phosphates may be critical for lung cancer treatment as well as prevention," Myung-Haing Cho, lead author of a report in the first January issue of American Journal of Respiratory and Critical Care Medicine, said in a statement.

But, "an individual shouldn't act on these results as yet, other than to encourage funding organizations such as the National Institutes of Health to support research to see whether dietary phosphates encourage cancer," said Dr. John Heffner, a professor of medicine at the Oregon Health & Science University in Portland and past president of the American Thoracic Society, which publishes the journal.

Natural sources of dietary phosphates include leafy vegetables, fruits, meats and poultry products. Phosphates also are added to a number of foods, including baking powder, carbonated cola drinks, ice cream, bread, rolls, macaroni, fruit jellies and preserves. Food phosphates are listed by the U.S. Food and Drug Administration as GRAS -- generally recognized as safe -- with no limits on their use.

The South Korean study was done with two breeds of laboratory mice, one genetically inclined to have lung cancer, the other with induced lung cancers. They were fed either diets containing phosphates in roughly the same amounts found in human diets or phosphates at twice that level. After four weeks, more and larger lung cancers were found in the rats given the higher-phosphate diets, the report said.

Phosphates appear to activate a metabolic pathway that stimulates the growth of the lung tumors, the researchers said.

There is "good scientific rationale" for believing that phosphates can stimulate the growth of lung cancers and other tumors in humans, Heffner said. But for lung cancer, he said, "the first thing is not to smoke." Genetics can also play a role in risk, Heffner added, since "some smokers get lung cancer, and some don't."

"I'll be more cautious about inspecting foods I ingest for phosphate addition, trying to keep dietary phosphate ingestion in the healthy range," he said.

However, the study was criticized as inadequate by Haley C. Stevens, scientific affairs specialist for the International Food Additives Council, whose members include manufacturers and users of phosphates.

"This new study is very limited and not comparable to the food industry's numerous toxicological studies, which use several different animal models of carcinogenesis, acute exposures and chronic exposures, and which clearly demonstrate the safety of phosphate-based food additives," Stevens said.

Studies are planned in South Korea to determine what the healthy range is, the researchers stated. In the 1990s, phosphate-containing food additives contributed an estimated 470 milligrams a day to the average adult diet. Their wider use has increased intake by as much as 1,000 milligrams a day, equivalent to the higher dose given to the rats in the experiment, Cho noted.

But Stevens took issue with that point: "...it should be noted that data on phosphate production do not indicate an increase in phosphate intake, as the study authors allege."

More information

Basic facts about lung cancer are available from the U.S. National Cancer Institute.

FRIDAY, Dec. 19 (HealthDay News) -- About a fifth of white Americans carry a gene mutation that leaves them at higher risk of colon cancer if they become chronic drinkers, a new study finds.

"If people drink alcohol chronically and have a certain genetic background, then they have an increased risk for large intestinal cancer -- colorectal cancer -- if they drink over a certain amount of alcohol every day," explained study co-author Dr. Helmut K. Seitz, a professor of medicine at Heidelberg University in Heidelberg, Germany.

Seitz and his colleagues were expected to publish their findings in the March issue of Alcoholism: Clinical and Experimental Research. The study was posted online Dec. 19.

Describing his team's work, Seitz said scientists have long known that chronic drinking ups risks for a wide range of cancers including breast, liver, esophageal and laryngeal malignancies.

In fact, the American Cancer Society already recommends limiting alcohol consumption to no more than one or two drinks per day for women and men, respectively, as a means of reducing overall cancer risk.

The new study focused on colon cancer. The team examined how disease risk might be affected by the varying speeds with which white individuals convert ethanol (alcohol) into a particularly metabolite called acetaldehyde.

This ethanol-to-acetaldehyde conversion process can be particularly rapid among those whites who carry a particular gene variant labeled ADH1C*1, the researchers noted.

"Acetaldehyde is a very toxic compound which changes and damages our DNA," Seitz noted. "And the speed of the change from ethanol to acetaldehyde is different in different individuals. So the idea is that if people have that gene which is responsible for a faster metabolism to acetaldehyde, then more of it would be produced in a shorter period of time, and more of would bind to our DNA. And that could increase colon cancer risk."

To explore this notion, the research team conducted genetic testing on 173 colon cancer patients, and compared their findings with tests conducted on 788 healthy people.

The result: Those men and women who possessed the ADH1C*1 gene were, in fact, at a genetically higher risk for developing colorectal cancer, although only when consuming more than 30 grams (about two drinks) of alcohol per day.

This translates to about a twofold to threefold increase in the risk for colon cancer for chronic drinkers with this particular genetic marker, Seitz said.

"But I have to state that, even so, the general risk is not tremendous," he noted. "Yes, it's certainly a significantly higher risk for those with the gene [about 20 percent of the general population] than for those without. But it's not an extremely huge risk."

"However, in any case, the message is very simple," added Seitz. "To be on the safe side, if you don't know your genetic background, be moderate in your alcohol consumption. That means you can have two drinks. But then be careful."

Dr. Marc Galanter, director of the division of alcoholism and substance abuse at New York University Langone Medical Center/Bellevue in New York City, noted that the current work serves to highlight another negative consequence of heavy alcohol use.

"Some develop liver disease," he said. "Others develop cardiac disease and, apparently, based on this study, some are more vulnerable to developing colorectal cancer. Research like this will help us understand which people are most vulnerable to the ill consequences of heavy drinking."

More information

There's more on the alcohol-cancer link at the American Cancer Society.