title: Significance of the association between heparin-binding epidermal growth factor-like growth factor and CD9 in human gastric cancer.
abstract: Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the EGF family. Juxtacrine activity of proHB-EGF (the membrane-anchored form of HB-EGF) has been shown to be significantly potentiated when it is coexpressed with CD9 in vitro. The purpose of our study was to investigate the issue of whether proHB-EGF and CD9 are coexpressed in gastric cancer. HB-EGF gene expression and protein production in human gastric cancers was investigated, and EGF receptor and CD9 expressions were also evaluated. HB-EGF mRNA levels in gastric cancers were elevated, compared with normal gastric tissues, especially in the intestinal type. ProHB-EGF immunoreactivity was detected primarily in the cytoplasm and plasma membrane of gastric cancer cells. Of 66 patients, 40 (60.6%) exhibited proHB-EGF immunoreactivity and the level of its expression was significantly associated with tumor status (p < 0.01) and histological differentiation (p < 0.001). In addition, proHB-EGF mRNA was detected at high levels in the intestinal type by in situ hybridization. CD9 immunoreactivity was found to be preserved in 26 of 36 patients (72.2%) and CD9 protein expression was inversely associated with lymph node status (p < 0.05). A significant correlation between its expression and histological differentiation (p < 0.01) was found, and the association of CD9 with proHB-EGF was increased in the intestinal type, as evidenced by an immunoprecipitation method. These results indicate that the coexpression of proHB-EGF and CD9 may be involved in the tumorigenesis and/or proliferation of gastric cancers in a juxtacrine manner.
authors.affiliation: Department of Internal Medicine and Molecular Science, Graduate School of Medicine, Osaka University, Yamadaoka, Suita, Osaka, Japan. yokom@imed2.med.osaka-u.ac.jp
authors.forename: Yoko
authors.initials: Y
authors.lastname: Murayama
authors.forename: Jun-ichiro
authors.initials: J
authors.lastname: Miyagawa
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Shinomura
authors.forename: Shuji
authors.initials: S
authors.lastname: Kanayama
authors.forename: Koji
authors.initials: K
authors.lastname: Isozaki
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yamamori
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mizuno
authors.forename: Shingo
authors.initials: S
authors.lastname: Ishiguro
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kiyohara
authors.forename: Yoshiji
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Higashiyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsuzawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D060245:Tetraspanin 29
chemical_list: D015703:Antigens, CD; C554869:CD9 protein, human; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D060245:Tetraspanin 29; D004815:Epidermal Growth Factor; D066246:ErbB Receptors