By now, several hypotheses have been proposed to explain TKI-induced hypothyroidism, including reduced synthesis of thyroid hormones [33], inhibition of thyroid uptake of iodine [39], atrophy of the thyroid owing to drug toxicity [36], preceding thyroiditis with associated transient thyrotoxicosis [40], and immune dysregulation [41]. This evidence concerns the gene TG and thyrotoxicosis.