The government is adding viruses for the first time to its list of known or suspected causes of cancer, including hepatitis B and C and a third virus that causes sexually transmitted diseases. Lead, X-rays and compounds in grilled meats also are joining the list, ABC News reported.
It has been known that the hepatitis viruses can cause liver cancer and that some forms of the sexually transmitted human papillomavirus can cause cervical cancer.
But they were added to the list Monday only after officials decided to go beyond the report's historical focus on the occupational and environmental causes of cancer, said Dr. Christopher Portier, associate director of the National Toxicology Program, which prepared the latest update.
Dr. Michael Thun, who runs the American Cancer Society's epidemiological program, said adding the viruses were important. "These are human carcinogens and very important carcinogens," he said.
The list, which now identifies 246 known or suspected cancer-causing agents, is intended to give people who may or may not be exposed to any of the substances something to think about, he said.
Take X-rays, added to the "known" category. But the American College of Radiology faulted the addition of X-rays and gamma rays, saying it was misleading and could prompt patients to avoid getting needed care.

Individual personality traits, such as conscientiousness, may affect a person's performance in testing or achievement situations and may, according to a Rice psychologist, explain why gender differences exist in test performance, psychport.com said.
While there are generally no gender differences found for intelligence tests, some differences have been found in tests of knowledge. A psychologist at Rice University suspects one explanation is that women and men might approach testing situations differently, and that might affect their performance.
"In looking at what people know and how they develop intellectually through their life span, I've found there are very pervasive gender differences in knowledge favoring men," says Margaret Beier, an assistant professor in psychology at Rice.
One area in which such gender differences have long been established is test performance. Why there may be differences in the performance levels of men and women regarding exams such as Advanced Placement tests is a puzzle Beier continues to pursue.
Cognitive ability is a strong predictor of educational or occupational performance, but researchers also know that certain personality traits such as conscientiousness add incremental prediction.
Beier hypothesizes that women might be more susceptible to a predisposition for anxiety and rumination that might affect their overall test performance.
In other research related to human intelligence, Beier has worked closely with Phillip Ackerman, a professor of psychology at Georgia Institute of Technology, on a number of projects examining the relationship between working memory ability and intelligence. One of those studies, recently reported in Intelligence, challenges the claim of a number of cognitive psychologists that working memory--the ability to keep something in memory while performing other tasks--is the same as intelligence.

New languages can develop consistent rules of grammar within a single generation of their birth, a study of an Israeli sign language has shown, nature.com said.
The Al-Sayyid Bedouins have a high rate of congenital deafness. In a population of about 3,500, roughly 150 people are deaf. The community, which was founded about 200 years ago, has developed its own sign language over the past 70 years, with no apparent outside influences. This is the first documented example of a language evolving from scratch in such isolation.
"We didn't expect to see word order so quickly, and didn't expect to see this particular word order," says Carol Padden of the University of California, San Diego, who led the study. The discovery suggests that grammar appears early in the development of face-to-face languages. Written language can take centuries to develop consistent grammar.
Speedy development in sign language has been seen before. Nicaraguan deaf people have adopted a common sign language over the past 25 years, since they were brought together in a specialist school system for the deaf.
But the Al-Sayyid Bedouins are the first group to be studied that has developed a sign language with no outside influence.
The language's rapid progress is impressive, agrees Steven Pinker, a linguist at Harvard University in Cambridge, Massachusetts.
But there is nothing remarkable about the contrast between the signers' SOV structure and the SVO grammar of Israel's spoken languages, he says. Languages are split between the two and some switch from one to the other, as shown by archaic English phrases that use SOV, such as "With this ring, I thee wed."
The simple structure of Al-Sayyid Bedouin sign language is an important convention that will allow later sophistication, say Padden and her colleagues.