These results suggest that HB-EGF could induce tyrosine phosphorylation of HER1 in the thyroid carcinoma cell lines expressing HER1, while in the thyroid carcinoma tissues expressing both of HER1 and HER4, HB-EGF might induce tyrosine phosphorylation of HER1 and/or HER4. The gene discussed is EGFR; the disease is thyroid gland carcinoma.