TUESDAY, Jan. 9, 2007 (HealthDay News) -- Acquired genetic changes appear to be linked to the development of some head and neck cancers, new research suggests.
U.S. scientists said they've discovered five genetic alterations in tissue surrounding head and neck cancer tumors that are associated with a tumor's aggressiveness. They also found three genetic changes that were associated with a tumor's size and ability to spread.
"We found genetic alterations in the innocent-looking cells around head and neck cancers," said the study's lead author, Dr. Charis Eng, chairwoman and director of the Genomic Medicine Institute at the Cleveland Clinic Foundation in Ohio. "Why and how these changes occur, we don't know."
Each year, about 31,000 Americans are diagnosed with head and neck cancer and about 7,400 die from the disease, according to background information in the study. While progress has been made in treatment, half of all people who develop this form of cancer will eventually die from it, reports the study.
About 85 percent of people who develop head and neck cancers are tobacco users, according to the National Cancer Institute (NCI). Alcohol use is also an important risk factor for this disease, and people who use both tobacco and alcohol have the greatest risk, according to the NCI.
To get a better understanding of how these cancers develop, researchers from the Cleveland Clinic and Case Western Reserve University examined cells from 122 head and neck cancer tumors and from surrounding tissue. All of the tissue samples came from people who smoked.
These samples underwent a whole genome analysis, with the researchers specifically looking for deletions in the genes, according to Eng.
The researchers discovered genetic alteration "hot spots" -- or compartments -- in the supposedly normal tissue surrounding the head and neck cancers. Five genetic alterations related to a tumor's aggressiveness were found, and three were linked to tumor size and its ability to spread, or metastasize. Another two hot spots were identified in the cells around the tumors, and these were associated with the tumors' ability to spread and appeared to be useful for staging of the disease.
"These are new biomarkers that can tell us which are aggressive tumors and which are not," Eng explained. And, she said, "Suddenly, instead of just targeting the tumor, we can work on developing therapies to target these new compartments."
However, she added that this work needs to be replicated by other researchers.
Eng said the researchers didn't design the study to identify what caused the genetic alterations, but that smoking likely plays a role in the development of cancerous cells. She said she wouldn't yet "make the leap" to say the genetic changes in the tissue around the cancer were caused by smoking, because that research hasn't been done. She did, however, say that these genetic alterations were acquired and not hereditary alterations.
Of the study, Dr. Jay Brooks, chairman of hematology and oncology at the Ochsner Clinic Health System in Baton Rouge, La., said, "With further work, these findings may help to identify specific genes that can predict aggressiveness."
He added that what's most important to take away from this study is that, "Once again, we have clear evidence that the carcinogens in tobacco affect cells that cause cancer and probably the cells surrounding the cancer. Carcinogens from tobacco bathe the area and may cause molecular alterations in the cells surrounding cancers."
More information
The American Academy of Otolaryngology has more information on head and neck cancer.
