title: Raf-1 kinase inhibitory protein expression in thyroid carcinomas.
abstract: Raf-1 kinase inhibitory protein (RKIP) has been implicated in several fundamental signal transduction pathways that control cellular growth, differentiation, apoptosis and migration. RKIP is reduced in a variety of human carcinomas, but RKIP expression in thyroid carcinomas has not been analyzed at the protein level. In this study, we examined the immunohistochemical expression of RKIP in various subtypes of thyroid carcinoma. Immunostaining for RKIP was performed on 104 cases of primary thyroid carcinoma (40 papillary, 29 follicular, 11 medullary, 11 poorly differentiated, and 13 anaplastic carcinomas) and 26 cases of nodal metastatic tumor (17 papillary, 4 medullary, and 5 anaplastic carcinomas). Normal thyroid tissue and all cases of follicular, papillary, and medullary carcinomas showed uniform, strong cytoplasmic immunoreactivity for RKIP. With the exception of one case, poorly differentiated carcinomas also revealed strong RKIP expression. In contrast, RKIP expression was completely absent in all anaplastic carcinomas. The transition zone from the differentiated carcinoma component (strong RKIP expression) to the anaplastic carcinoma component (no RKIP expression) demonstrated a completely opposite pattern of RKIP immunoreactivity. This reduction of RKIP expression in anaplastic carcinoma was statistically significant (P < 0.0001). Additionally, RKIP expression of nodal metastatic tumors corresponded with that of primary tumors: metastatic papillary and medullary carcinomas showed uniform, strong cytoplasmic RKIP immunoreactivity, in contrast, in metastatic anaplastic carcinomas, RKIP expression was completely absent. RKIP expression is significantly reduced in anaplastic thyroid carcinoma as compared to other subtypes of thyroid carcinoma. Further studies are necessary to elucidate the precise mechanism of RKIP action in anaplastic thyroid carcinoma.
authors: Department of Pathology, Graduate School of Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, 130-702 Seoul, Republic of Korea.
authors: Hyun-Soo
authors: HS
authors: Kim
authors: Gou Young
authors: GY
authors: Kim
authors: Sung-Jig
authors: SJ
authors: Lim
authors: Youn Wha
authors: YW
authors: Kim
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology; D018276:Carcinoma, Medullary / Q000378:metabolism / Q000473:pathology; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D049488:Phosphatidylethanolamine Binding Protein / Q000096:biosynthesis*; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: C511482:PEBP1 protein, human; D049488:Phosphatidylethanolamine Binding Protein