title: Protein and gene expression of tumor-associated antigen RCAS1 in esophageal squamous cell carcinoma.
abstract: RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is expressed on the tumor cell membrane and induces apoptosis on infiltrated immune lymphocytes. RCAS1 has been reported to correlate with the escape of tumor cells from host immune surveillance, and with poor prognosis. However, the clinical importance of RCAS1 protein and gene expression in esophageal squamous cell carcinoma (ESCC) has not been well investigated. In the present study, RCAS1 gene and protein expression levels were evaluated and compared with clinical findings in 67 patients with ESCC. Expression levels of RCAS1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) messenger RNAs (mRNAs) from tumors and non-cancerous epithelia were analyzed quantitatively by real-time reverse transcriptase polymerase chain reaction (RT-PCR). RCAS1 protein expression was analyzed by immunohistochemistry. The mean RCAS1/GAPDH ratio of tumors (0.7) was not different from that of non-cancerous epithelia (0.7, p=0.715). RCAS1 immunoreactivity was detected in 19 tumors (28.4%). The mean RCAS1/GAPDH ratio of tumors with RCAS1 protein positive (0.6) did not differ from tumors without RCAS1 expression (0.8, p=0.131). RCAS1 gene and protein expressions did not correlate with tumor size, depth of invasion, lymph node metastasis, or patient prognosis. Thus, RCAS1 gene or protein expression may not correlate with tumor progression in ESCC.
authors.affiliation: Division of Operating Room, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan. masaike@grape.med.tottori-u.ac.jp
authors.forename: Masahide
authors.initials: M
authors.lastname: Ikeguchi
authors.forename: Shotaro
authors.initials: S
authors.lastname: Ohoro
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maeda
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Fukuda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shirai
authors.forename: Akira
authors.initials: A
authors.lastname: Kondo
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Tsujitani
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kaibara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000951:Antigens, Neoplasm; D018076:DNA, Complementary; C120762:EBAG9 protein, human; D012333:RNA, Messenger