We investigated the presence and patterns of mosaicism in the APC gene in patients with colon neoplasms not associated with any other genetic variants; we performed deep sequence analysis of APC in at least 2 adenomas or carcinomas per patient. We identified mosaic variants in APC in adenomas from 9 of the 18 patients with 21 to approximately 100 adenomas. Mosaic variants of APC were variably detected in leukocyte DNA and/or non-neoplastic intestinal mucosa of these patients. In a comprehensive sequence analysis of 1 patient, we found no evidence for mosaicism in APC in non-neoplastic intestinal mucosa. One patient was found to carry a mosaic c.4666dupA APC variant in only 10 of 16 adenomas, indicating the importance of screening 2 or more adenomas for genetic variants.

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doi.org/10.1053/j.gastro.2016.10.040, hdl.handle.net/1765/95757
Department of Pathology

Jansen, A.M.L. (Anne M.L.), Crobach, S., Geurts-Giele, I., van den Akker, B.E.W.M. (Brendy E.W.M.), Garcia, M.V. (Marina Ventayol), Ruano, D., … Morreau, H. (2017). Distinct Patterns of Somatic Mosaicism in the APC Gene in Neoplasms From Patients With Unexplained Adenomatous Polyposis. Gastroenterology, 152(3), 546–549.e3. doi:10.1053/j.gastro.2016.10.040