Transposable elements contribute to tumor growth
An NIEHS-funded study revealed that transposable elements, which are sequences of DNA that move around in the genome, are important drivers of tumor growth. The study provides the first comprehensive look at the role transposable elements play in activating cancer genes.
Typical genome sequencing methods that look for genetic mutations that drive cancer do not detect transposable elements. So the researchers used more powerful sequencing techniques to analyze 7,769 tumor samples from 15 different types of cancer. They discovered 129 transposable elements that played a part in tumor growth by influencing 106 different cancer genes. The authors reported that transposable elements switch on cancer-related genes that are usually silent and keep them switched on.
At least one transposable element activated a cancer gene in about half of all the tumors studied. Although transposable elements were widespread, the pattern of transposable elements varied across cancer types. For example, 87% of tumor samples from a type of lung cancer called squamous cell carcinoma had at least one transposable element, but this was only 12% for glioma brain cancers.
According to the authors, a better understanding of transposable elements may provide more information about what leads to accelerated tumor growth in some cancers and new targets to study for future cancer therapies.
Citation: Jang HS, Shah NM, Du AY, Dailey ZZ, Pehrsson EC, Godoy PM, Zhang D, Li D, Xing X, Kim S, O'Donnell D, Gordon JI, Wang T. 2019. Transposable elements drive widespread expression of oncogenes in human cancers. Nat Genet 51(4):611–617.