AUTHOR=Huang Wei , Bian Jin , Qian Xiaoping , Shao Lin , Li Haiyan , Zhang Lu , Wang Lin 

TITLE=Case Report: Coinheritance of Germline Mutations in APC and BRCA1 in Colorectal Cancer

JOURNAL=Frontiers in Oncology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.658389

DOI=10.3389/fonc.2021.658389

ISSN=2234-943X

ABSTRACT=<p>Deleterious mutations in <italic>APC</italic> gene cause the autosomal dominant familial adenomatous polyposis (FAP) which is typically characterized by the occurrence of hundreds to thousands of colorectal adenomas that eventually lead to colorectal cancers (CRCs). <italic>BRCA1/2</italic> are the two major susceptibility genes for breast and ovarian cancers. Here, we reported a coinheritance of mutations in <italic>APC</italic> and <italic>BRCA1</italic> genes in a 20-year-old CRC patient with typical clinical features for FAP. Multiple relatives in the family of the patient were affected by colorectal and other cancers. Next-generation sequencing analysis using a panel consisting of 53 hereditary cancer related genes revealed a maternally inherited <italic>APC</italic> (exon15cn_del) mutation and a paternally inherited <italic>BRAC1</italic> (p.lle1824AspfsX3) mutation. This is the first coexistence of <italic>APC</italic> and <italic>BRCA1</italic> mutations in a CRC patient with the mutation inheritance pattern comprehensively characterized in the family. The patient underwent a colonoscopy and a subtotal colectomy and was subsequently diagnosed with colonic adenocarcinomas accompanied with hundreds of tubulovillous adenomas. The case reveals the scenario where two disease-causing mutations of different hereditary tumor syndromes coexist, and illustrates the importance of evaluating detailed family history and performing a multiple-gene panel test in patients with hereditary cancer.</p>