Tobacco May Activate Cancer-Causing Virus in the Body
Oct. 5, 1999 (Cleveland) -- The Epstein-Barr virus, the same virus that causes infectious mononucleosis, or "mono," may interact with tobacco to promote cancers of the mouth and throat, according to a study presented Monday at the 103rd meeting of the American Academy of Otolaryngology-Head and Neck Surgery in New Orleans.
About 3% of all cancers are oral cancers, with 30,000 new oral cancers diagnosed each year in the U.S. Almost all oral cancers are linked to tobacco use, whether the product is a cigarette, pipe, or chewing tobacco, say cancer experts. Although tobacco is known to cause cellular damage, researchers from Mount Sinai School of Medicine in New York City theorized that damage to tissue might also contribute to oral cancer. Proteins manufactured by the Epstein-Barr virus when the virus is in its active phase may cause that tissue damage.
The Epstein-Barr virus (EBV) commonly exists in a latent, or nonactive, state in humans, says lead investigator Derrick I. Wallace, MD, a resident in the department of otolaryngology at Mount Sinai Hospital. But when the virus is "turned on," it produces these cancer-causing proteins, he says. Wallace and his colleagues studied cancerous cells obtained from the mouth and throat looking for the presence of the EBV proteins. He says that most of the cell lines "had some of these gene products." EBV has been previously implicated in oral cancers as well as other malignant disorders.
Wallace's team knew that extracts from a very large plant family common in South China and Central Africa are capable of activating EBV. Tung oil is one of these extracts, he says. He theorized that tobacco extracts could have the same effect.
The researchers exposed EBV cells to increasing amounts of tobacco extracts for 30 hours. When they examined the cells after this exposure they found that tobacco worked just the same as tung oil in activating the virus. Moreover, they discovered that when they increased the amount of tobacco extract, the EBV cells reproduced more quickly.
Wallace tells WebMD that he thinks tobacco is causing oral cancers in two ways. "First it harms the ... cells, and then it activates the virus," says Wallace. Once activated, the virus produces the cancer-causing proteins that damage the tissue. But although he is comfortable with this theory, he says that his study does not establish a causal link between EBV and oral cancers.
"Our next step is to study biopsy tissue to determine if these EBV protein products are present in malignant tissue," he says. If so, "that would establish causality."
Tobacco May Activate Cancer-Causing Virus in the Body
Oct. 5, 1999 (Cleveland) -- The Epstein-Barr virus, the same virus that causes infectious mononucleosis, or "mono," may interact with tobacco to promote cancers of the mouth and throat, according to a study presented Monday at the 103rd meeting of the American Academy of Otolaryngology-Head and Neck Surgery in New Orleans.
About 3% of all cancers are oral cancers, with 30,000 new oral cancers diagnosed each year in the U.S. Almost all oral cancers are linked to tobacco use, whether the product is a cigarette, pipe, or chewing tobacco, say cancer experts. Although tobacco is known to cause cellular damage, researchers from Mount Sinai School of Medicine in New York City theorized that damage to tissue might also contribute to oral cancer. Proteins manufactured by the Epstein-Barr virus when the virus is in its active phase may cause that tissue damage.
The Epstein-Barr virus (EBV) commonly exists in a latent, or nonactive, state in humans, says lead investigator Derrick I. Wallace, MD, a resident in the department of otolaryngology at Mount Sinai Hospital. But when the virus is "turned on," it produces these cancer-causing proteins, he says. Wallace and his colleagues studied cancerous cells obtained from the mouth and throat looking for the presence of the EBV proteins. He says that most of the cell lines "had some of these gene products." EBV has been previously implicated in oral cancers as well as other malignant disorders.
Wallace's team knew that extracts from a very large plant family common in South China and Central Africa are capable of activating EBV. Tung oil is one of these extracts, he says. He theorized that tobacco extracts could have the same effect.
The researchers exposed EBV cells to increasing amounts of tobacco extracts for 30 hours. When they examined the cells after this exposure they found that tobacco worked just the same as tung oil in activating the virus. Moreover, they discovered that when they increased the amount of tobacco extract, the EBV cells reproduced more quickly.
Wallace tells WebMD that he thinks tobacco is causing oral cancers in two ways. "First it harms the ... cells, and then it activates the virus," says Wallace. Once activated, the virus produces the cancer-causing proteins that damage the tissue. But although he is comfortable with this theory, he says that his study does not establish a causal link between EBV and oral cancers.
"Our next step is to study biopsy tissue to determine if these EBV protein products are present in malignant tissue," he says. If so, "that would establish causality."
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