While several inherited conditions have been associated with thyroid cancer, the precise primary cause of most cases is unknown. Alterations in an individual's DNA can prompt the transformation of thyroid cells into cancerous ones. Certain risk factors can increase the likelihood of thyroid cancer, such as for individuals with particular benign thyroid conditions. For those with a history of benign breast conditions, the risk of thyroid cancer doubles in comparison to those without such a history. Being overweight also escalates the risk of thyroid cancer compared to individuals of lower weight. Additionally, a familial history of thyroid cancer can heighten an individual's vulnerability to the disease.