{Reference Type}: Review
{Title}: De novo familial adenomatous polyposis associated thyroid cancer with a c.2929delG frameshift deletion mutation in APC: a case report and literature review.
{Author}: Xu M;Zheng Y;Zuo Z;Zhou Q;Deng Q;Wang J;Wang D;
{Journal}: World J Surg Oncol
{Volume}: 21
{Issue}: 1
{Year}: Mar 2023 2
{Factor}: 3.253
{DOI}: 10.1186/s12957-023-02951-9
{Abstract}: <B>BACKGROUND: </B>Germline mutations in the APC gene located on chromosome 5q 21-22 can lead to familial adenomatous polyposis (FAP) and the development of colorectal cancer (CRC) if left untreated. As a rare extracolonic manifestation, thyroid cancer is diagnosed in about 2.6% of FAP patients. The genotype-phenotype correlation in FAP patients with thyroid cancer remains unclear.<BR><B>METHODS: </B>We present a 20-year-old female of FAP with thyroid cancer as the initial manifestation. The patient was asymptomatic and developed colon cancer liver metastases 2 years after the diagnosis of thyroid cancer. The patient underwent multiple surgical treatments in several organs, and regular colonoscopy with endoscopic polypectomy was performed. Genetic testing demonstrated the c.2929delG (p.Gly977Valfs*3) variant in exon 15 of the APC gene. This represents a previously undescribed APC mutation. This mutation causes loss of multiple structures on the APC gene including the 20-amino acid repeats, the EB1 binding domain, and the HDLG binding site, which may be pathogenic through β-catenin accumulation, cell cycle microtubule dysregulation, and tumor suppressor inactivation.<BR><B>CONCLUSIONS: </B>We report a de novo FAP case with thyroid cancer presenting atypically aggressive features harboring a novel APC mutation and review APC germline mutations in patients with FAP-associated thyroid cancer.