title: Overexpression of human tumor-associated antigen, RCAS1, is significantly linked to dedifferentiation of thyroid carcinoma.
abstract: OBJECTIVE
  Counterattack by RCAS1 on carcinoma to cytotoxic T cells and natural killer (NK) cells has been suggested as a contribution to carcinoma progression, because RCAS1 can inhibit their proliferation and induce apoptosis. In this study, we examined RCAS1 expression in various thyroid neoplasms in order to clarify its clinical significance.
  
  
  METHODS
  We studied RCAS1 expression by means of immunohistochemistry using a mouse monoclonal antibody against RCAS1 for normal thyroid epithelium, follicular adenoma, follicular carcinoma, papillary carcinoma and undifferentiated (anaplastic) carcinoma.
  
  
  RESULTS
  Normal epithelium and follicular adenoma did not express or only faintly expressed RCAS1. In thyroid carcinomas. RCAS1 overexpression was more frequently observed in anaplastic (undifferentiated) carcinomas than papillary (p < 0.0001) and follicular carcinomas (p = 0.0018). In follicular carcinoma, the widely invasive type more frequently overexpressed RCAS1 than the minimally invasive type (p = 0.0488). Furthermore, the incidences of RCAS1 overexpression increased with carcinoma dedifferentiation (p < 0.0001).
  
  
  CONCLUSIONS
  These results suggest that RCAS1 may contribute to the progression of thyroid carcinoma with high biological aggressiveness.
authors.affiliation: Kuma Hospital, Kobe, Japan. ito01@kuma-h.or.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshida
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakano
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hirai
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
authors.forename: Nariaki
authors.initials: N
authors.lastname: Matsuura
authors.forename: Kanji
authors.initials: K
authors.lastname: Kuma
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000473:pathology; D000236:Adenoma / Q000378:metabolism / Q000473:pathology; D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D002454:Cell Differentiation; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C120762:EBAG9 protein, human; D019394:Ki-67 Antigen