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In the United States, thyroid cancer makes up about 3 percent of cases, according to the National Cancer Institute. While many cases of thyroid cancer are sporadic, genetics play a role in several cases.
The Cleveland Clinic noted that 5 to 10 percent of cases result from genetic mutations. Research has identified genes that contribute to thyroid cancer.
Mutations to the REarranged during Transfection proto-oncogene, or RET gene, account for about 20 to 25 percent of medullary thyroid cancer cases, noted the National Cancer Institute.
Located on chromosome 10q11.2, the RET gene is involved in the production of proteins responsible for intracellular signaling. The mutations to this gene may result in multiple endocrine neoplasia type 2A, multiple endocrine neoplasia type 2B and familial medullary thyroid cancer.
Genetics Home Reference pointed out that more than 25 mutations to the gene result in multiple endocrine neoplasia type 2. Since multiple endocrine neoplasia type 2 is an autosomal dominant disorder, a child of an affected parent has a 50/50 chance of inheriting the mutation.
Genetic testing may be used to identify the mutation to the RET gene. Germline deoxyribonucleic acid-based testing can detect the mutated RET gene in more than 95 percent of patients with multiple endocrine neoplasia type 2A and 2B, and about 88 percent of patients with familial medullary thyroid cancer, stated the National Cancer Institute.
Another gene associated with thyroid cancer is the adenomatous polyposis coli, or APC gene. Located on chromosome 5q21-q22, the APC gene may cause familial adenomatous polyposis when mutated. Genetic Home Reference noted that over 700 mutations to the APC gene result in familial adenomatous polyposis, a disorder in which patients develop multiple benign polyps that can become malignant.
Patients with familial adenomatous polyposis have a higher risk of developing other types of cancer, including thyroid cancer.