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. This evidence concerns the gene HBEGF and thyroid gland carcinoma.