ATLANTA (CBS Atlanta) – According to a new study, genes that are linked to good health could also increase the risk of brain cancer.
This research may be the first of its kind to determine that the protective stretches of DNA found at the ends of chromosomes have an increased risk of cancer.
Previous studies had led scientist to believe that people with increasing telomere length might protect cells from the effects of aging. “Shorter telomere length has previously been linked with cancer,” Kyle Walsh, a genetic epidemiologist at the University of California, San Francisco, and lead author on this study, told LiveScience. “However, direct measurement of telomere length is complicated, because telomeres shorten with age, and cancer rates increase with age. As a result, the relationship between telomere length and cancer has previously been clouded by the effects of aging.”
Walsh and his team took a look at glioma in order to see a link between cancer and telomere length. Glioma is a type of tumor that starts in the brain. Gliomas make up about 80 percent of all brain and central nervous system tumors and 30 percent of all malignant brain tumors.
Researchers analyzed the genomes of 1,644 patients with glioma and the genomes of 7,736 healthy people. They were able to confirm that there is a link between gliomas and a gene known as TERT. Telomerase reverse transcriptase is a catalytic subunit of the enzyme telomerase, which, together with the telomerase RNA component, or TERC, comprises the most important unit of the telomerase complex, which is the enzyme that controls the length of telomeres.
Researchers were able to determine that variants of both TERT and TERC were associated with glioma risk and also linked to greater telomere length.
“Lengthened telomeres are generally considered to be a marker of healthy aging,” Walsh said. “However, our data indicate they may simultaneously increase the risk of malignant brain tumors.”
Researchers did note that even though these variants carry a higher risk of gliomas, they may improve overall health.
“It’s not uncommon for people diagnosed with glioma to comment, ‘I’ve never been sick in my life,’” Margaret Wrensch, of the University of California, San Francisco, and senior author on this study, said in a statement obtained by LiveScience.
“Though longer telomeres might be good for you as a whole person – reducing many health risks and slowing aging – they might also cause some cells to live longer than they’re supposed to, which is one of the hallmarks of cancer,” Walsh said in a statement.
Glioma is an uncommon disease. “So even something that doubles risk still results in a very low lifetime risk of developing this cancer,” Walsh said.
TERT has been linked to lung, prostate, testicular, and breast cancer, and TERC is linked to leukemia, colon cancer, and multiple myeloma.
“A promising future line of investigation will be to see whether these variants are linked with shorter or longer telomeres,” Walsh said.
The Centers for Disease Control and Prevention characterize malignant tumors into two categories, carcinomas and sarcomas. Carcinomas are the most common type of cancer.
The findings were published in the online journal Nature Genetics.