IGF1 and thyroid gland follicular carcinoma: In comparison with follicular carcinomas, HCCs express a greater proportion of Pan-ras, N-myc, transforming growth factor alpha (TGF-α), TGF-β and insulin-like growth factor 1 (IGF-1).12 So, these findings confirm that HCCs and follicular carcinomas are different entities and not only a subtype one of the other.