title: Loss of claudin-7 is a negative prognostic factor for invasion and metastasis             in oral squamous cell carcinoma.
abstract: Claudin-7 belongs to the claudin family, which consists of 24 subtypes of essential tight junction (TJ) integral membrane proteins with molecular weights of 20-27 kDa. We investigated the interrelationship between clinicopathological findings and claudin-7 expression in oral squamous cell carcinoma (OSCC). Using immunohistochemical techniques to examine the expression levels of claudin-7 in 67 cases of OSCC, claudin-7 expression was detected in 35 (52.2%) of the 67 cases. We also compared the clinicopathological features of the OSCC cases with claudin-7 expression levels. Moreover, six cell lines with various invasive properties were investigated in vitro to compare mRNA and protein levels of claudin-7 using reverse transcription-polymerase chain reaction (RT-PCR) and the western blotting method. Decreased claudin-7 expression correlated significantly with T-category (p<0.05), lymph node metastasis (p<0.01), and mode of invasion (p<0.001). Patients with positive claudin-7 expression had a significantly better prognosis (p<0.05). Claudin-7 protein and mRNA levels were lower in the HOC313 and TSU cells, which have higher invasive potentials compared with other cell lines. These results suggest that loss of claudin-7 expression is associated closely with invasion and lymph metastasis and is an unfavorable prognostic factor in patients with OSCC.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa 920-8641, Japan. yoshizawa@oral.m.kanazawa-u.ac.jp
authors.forename: Kunio
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nozaki
authors.forename: Aki
authors.initials: A
authors.lastname: Kato
authors.forename: Mariko
authors.initials: M
authors.lastname: Hirai
authors.forename: Mizuki
authors.initials: M
authors.lastname: Yanase
authors.forename: Taisuke
authors.initials: T
authors.lastname: Yoshimoto
authors.forename: Iyo
authors.initials: I
authors.lastname: Kimura
authors.forename: Shiro
authors.initials: S
authors.lastname: Sugiura
authors.forename: Ayako
authors.initials: A
authors.lastname: Okamune
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kitahara
authors.forename: Natsuyo
authors.initials: N
authors.lastname: Noguchi
authors.forename: Koroku
authors.initials: K
authors.lastname: Kato
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ueki
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kawashiri
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000556:secondary*; D045744:Cell Line, Tumor; D057167:Claudins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D015996:Survival Rate; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C473255:CLDN7 protein, human; D015820:Cadherins; D057167:Claudins; D012333:RNA, Messenger; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors