@article{Ewing01102015, author = {Ewing, Adam D. and Gacita, Anthony and Wood, Laura D. and Ma, Florence and Xing, Dongmei and Kim, Min-Sik and Manda, Srikanth S. and Abril, Gabriela and Pereira, Gavin and Makohon-Moore, Alvin and Looijenga, Leendert H.J. and Gillis, Ad J.M. and Hruban, Ralph H. and Anders, Robert A. and Romans, Katharine E. and Pandey, Akhilesh and Iacobuzio-Donahue, Christine A. and Vogelstein, Bert and Kinzler, Kenneth W. and Kazazian, Haig H. and Solyom, Szilvia}, title = {Widespread somatic L1 retrotransposition occurs early during gastrointestinal cancer evolution}, volume = {25}, number = {10}, pages = {1536-1545}, year = {2015}, doi = {10.1101/gr.196238.115}, abstract ={Somatic L1 retrotransposition events have been shown to occur in epithelial cancers. Here, we attempted to determine how early somatic L1 insertions occurred during the development of gastrointestinal (GI) cancers. Using L1-targeted resequencing (L1-seq), we studied different stages of four colorectal cancers arising from colonic polyps, seven pancreatic carcinomas, as well as seven gastric cancers. Surprisingly, we found somatic L1 insertions not only in all cancer types and metastases but also in colonic adenomas, well-known cancer precursors. Some insertions were also present in low quantities in normal GI tissues, occasionally caught in the act of being clonally fixed in the adjacent tumors. Insertions in adenomas and cancers numbered in the hundreds, and many were present in multiple tumor sections, implying clonal distribution. Our results demonstrate that extensive somatic insertional mutagenesis occurs very early during the development of GI tumors, probably before dysplastic growth.}, URL = {http://genome.cshlp.org/content/25/10/1536.abstract}, eprint = {http://genome.cshlp.org/content/25/10/1536.full.pdf+html}, journal = {Genome Research} }