Beyond familial adenomatous polyposis: using genotype-phenotype correlations to discern germline versus somatic status for APC whole gene deletions among 860,000 tests

Presenting Author: Katherine L. Belshe, MS, CGC from the University of Kansas

Take home points: 

1. APC whole-gene deletions are incidentally identified in pan-cancer-panel-tested individuals but are most often reported as mosaic.
2. Mosaic APC whole-gene deletions were older than heterozygous individuals and had a cancer history that was distinct from FAP.
3. Breakpoint analysis revealed that the size of the deletion was highly variable in the mosaic cohort while the heterozygous cohort had on average a smaller deletions

• Speakers: Katherine L. Belshe; Jordyn Koehn; Alisdair Philp; Bryson Katona; Stephen Hyter; Rashna Madan; Barry Skikne; Abdulraheem Yacoub; Andrew K. Godwin; Marcy E. Richardson; Cassidy Carraway; Jeffrey N. Weitzel; Ajay Bansal
• Collaborators: Perelman School of Medicine at the University of Pennsylvania; University of Kansas Cancer Center
• Conference: CGA-IGC 2025
• Date: Saturday, Oct 11, 2025 1:30pm - 3:00pm