Risk Factors and Causes
Desmoid tumors can develop in individuals with familial adenomatous polyposis (FAP), an inherited form of colon cancer. However, the more common occurrence is sporadic desmoid tumors, which are primarily caused by somatic gene mutations. Unlike genetic mutations present at birth, somatic gene mutations occur later in life. Two specific genes, namely CTNNB1 and APC, are responsible for these mutations and subsequently the development of desmoid tumors. CTNNB1 gene mutations account for approximately 85% of sporadic desmoid tumors, while APC gene mutations are associated with FAP and contribute to approximately 15% of sporadic desmoid tumors.
Understanding FAP
Familial Adenomatous Polyposis (FAP) is a genetic condition that occurs due to a mutation in one copy of the APC gene. Individuals with FAP have an increased risk of developing abnormal growths or polyps, as well as cancerous tumors in the colon. In some cases, a second mutation in the APC gene can lead to the formation of desmoid tumors, which are typically found within the abdomen. This particular manifestation of FAP is referred to as hereditary desmoid disease, aggressive fibromatosis, or familial infiltrative fibromatosis by experts.