c-Met expression of thyroid tissue with special reference to papillary carcinoma.
It has become clear that papillary carcinomas of the thyroid often express the receptor for c-Met/hepatocyte growth factor (HGF) receptor, but little is known about the role of the HGF and c-Met system in the pathogenesis of thyroid carcinoma. In this study, the expression of c-Met/HGF receptor was evaluated in thyroid tissue by western blot and immunohistochemistry, and compared with the concentration of HGF. Clinicopathological characteristics were also compared. Fifteen of 20 papillary carcinomas (75%) showed c-Met bands of 145 kDa. No or only a low frequency of c-Met expression was detected in healthy thyroid tissue (0/5), thyroiditis or Basedow's disease (0/2), adenomatous goiters (0/8), follicular adenomas (1/9, 11%) and undifferentiated carcinomas (0/2). These results were confirmed by immunohistochemistry, but a relatively higher frequency of c-Met expression was detected in adenomatous goiters (25%), follicular adenoma (44%) and papillary carcinoma (100%) using formalin-fixed and paraffin-embedded materials. A strong immunoreaction for c-Met was observed in the tumor cytoplasm of papillary carcinomas among the fibrous tissues situated at the periphery of the tumor. The densitometrically measured expression of c-Met had no relation to tumor stage in papillary carcinoma, but did correlate to the concentration of HGF in papillary carcinomas. In conclusion, in thyroid lesions, c-Met was highly expressed specifically in the cytoplasm of papillary carcinomas. c-Met expression was not related to the aggressiveness of the tumor but was related to the concentration of HGF, which was probably derived from the stroma. Also, the c-Met system might play a role in the pathogenesis of papillary carcinoma of the thyroid.
Oyama
T
T
Second Department of Pathology, Gunma University School of Medicine, Maebashi, Japan. oyama@news.sb.gunma-u.ac.jp
Ichimura
E
E
Sano
T
T
Kashiwabara
K
K
Fukuda
T
T
Nakajima
T
T
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D002291:Carcinoma, Papillary / Q000378:metabolism* / Q000473:pathology; D006044:Goiter, Nodular / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D009367:Neoplasm Staging; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology
D019859:Proto-Oncogene Proteins c-met