These data may indicate the hypothesis as follows; when proHB-EGF can be enzymatically cleaved to rapidly release sHB-EGF in undifferentiated thyroid carcinoma cells, the tumor cells can show cell growth and migration rapidly through HER1 and/or HER4 by binding with sHB-EGF. Here, EGFR is linked to thyroid gland undifferentiated (anaplastic) carcinoma.