Paired box gene 8 is necessary for the formation of thyroxine-producing follicular cells in the thyroid gland (Mansouri et al, 1998, 1999); and fusion of the Pax-8 and peroxisome proliferator-activated receptor γ (PPARγ) genes occurs in approximately 30% of follicular thyroid carcinomas (Kroll et al, 2000; Dwight et al, 2003). The gene discussed is PAX8; the disease is thyroid gland follicular carcinoma.