Cancerous growth is a multifactorial biological process with several factors contributing to the growth of cancer cells in the body. A new study has revealed DNA left over from ancient viruses can support the growth of cancer cells.
The study published in the journal Science Advances has found that fragments of DNA from viruses act like switches for genes that help grow tumors.
LTR10 gene
The researchers found that LTR10, one virus-derived DNA fragment, was found in a variety of cancers including cancers like colorectal, lung, bile duct and stomach.
LTR10 comes from a retrovirus that, the researchers say, incorporated into the genome of human beings 30 million years ago and helped turn on several cancer related genes. “The activity of these [virus fragments] from many millions of years ago has shaped how disease manifests today,” Dr. Chuong, Ph.D., of the University of Colorado Boulder's BioFrontiers Institute said.
The researchers have said that strategies to silence the LTR10 sequences could help in a better way in cancer therapy.
Cancer related proteins like AP1 and MAPK unmask LTR10 sequences, which is why they remain closed in healthy tissues and act in cancer cells.
How did LTR10 genes become a part of the human body?
"Studies show about 8% of the human genome is made up of endogenous retroviruses that slipped into the cells of our evolutionary ancestors, coaxing their hosts to copy and carry their genetic material. Over time, they infiltrated sperm, eggs and embryos, baking their DNA like a fossil record into generations to come—and shaping evolution along the way," the researchers have explained.
To study the impact of LTR10 genes the scientists analyzed 21 human cancer types. "They found that a specific lineage of endogenous retrovirus known as LTR10, which infected some primates about 30 million years ago, showed surprisingly high levels of activity in several types of cancer, including lung and colon cancer. Further analysis of tumors from dozens of colorectal cancer patients revealed that LTR10 was active in about a third of them," the University of Colorado has said in an official statement.
