In many patients with hypothyroidism or hyperthyroidism, lymphocytes produce antibodies against their own thyroid gland. Common antibodies that cause thyroid problems are thyroid-specific peroxidase (TPO), TSH receptor (TSHR) autoantibodies, and antithyroglobulin antibodies.

Thyroid cancer accounts for only 1-2% of all cancers, but accounts for 90% of cancers of the endocrine glands and ranks 9th among cancers in women. However, thyroid diseases are still often left undiagnosed in 20-60% of the total population.