For breast cancer patients, studies did not directly show chemotherapy can influence thyroid function, only found some results indicative hypothyroidism, such as elevated concentrations of thyroid stimulating hormone (TSH), thyroperoxidase antibody (anti-TPO), thyroglobulin antibody (anti-Tg) [7] and decreased T3 uptake levels [8]. The gene discussed is TPO; the disease is breast carcinoma.