Overexpression of human tumor-associated antigen, RCAS1, is significantly linked to dedifferentiation of thyroid carcinoma.
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.
Ito
Yasuhiro
Y
Kuma Hospital, Kobe, Japan. ito01@kuma-h.or.jp
Yoshida
Hiroshi
H
Nakano
Keiichi
K
Kobayashi
Kaoru
K
Yokozawa
Tamotsu
T
Hirai
Keisuke
K
Matsuzuka
Fumio
F
Matsuura
Nariaki
N
Kuma
Kanji
K
Miyauchi
Akira
A
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
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C120762:EBAG9 protein, human; D019394:Ki-67 Antigen