title: Expression of ERBB3 binding protein 1 (EBP1) in salivary adenoid cystic carcinoma and its clinicopathological relevance.
abstract: BACKGROUND
  ERBB3 binding protein 1 (EBP1) gene transfer into human salivary adenoid cystic carcinoma cells has been shown to significantly inhibit cell proliferation and reduce tumor metastasis in mouse models. In the current study, to evaluate if EBP1 is a novel biomarker capable of identifying patients at higher risk of disease progression and recurrence, we examined the EBP1 expression profile in adenoid cystic carcinoma (ACC) patients and analyzed its clinicopathological relevance. To understand the underlying anti-metastatic mechanism, we investigated if EBP1 regulates invasion-related molecules.
  
  
  METHODS
  We performed immunohistochemical analysis on 132 primary adenoid cystic carcinoma and adjacent non-cancerous tissues using commercial EBP1, MMP9, E-cadherin and ICAM-1 antibodies. Results were correlated to clinicopathological parameters, long-term survival and invasion-related molecules by statistical analysis. Cell motility and invasiveness of vector or wild-type EBP1-transfected ACC-M cell lines were evaluated using wound healing and Boyden chamber assays. MMP9, E-cadherin and ICAM-1 proteins in these cell lines were detected using western blot assay.
  
  
  RESULTS
  The expression of EBP1 was significantly higher in non-cancerous adjacent tissues compared with corresponding cancer tissues. The intensity and percentage of cells that reacted with EBP1 antibodies were significantly higher in cases with tubular pattern than those with solid pattern (P<0.0001). We also found adenoid cystic carcinoma with local lymphatic metastasis had significantly lower EBP1 expression than ACC with no local lymphatic node metastasis (P<0.0001). Similar findings were observed in ACC with lung metastasis compared with cases with no lung metastasis (P<0.0001), in particular, in cases with perineural invasion compared with cases with no perineural invasion (P<0.0001). Furthermore, a decrease in EBP1 expression was positively associated with a reduction in overall survival of ACC patients. Of note, EBP1 inhibits migration and invasiveness of ACC cells by upregulating E-cadherin but downregulating MMP9. In clinical adenoid cystic carcinoma patients, higher EBP1 expression was positively correlated with E-cadherin levels (P<0.001) but negatively correlated with MMP9 expression (P=0.0002).
  
  
  CONCLUSIONS
  EBP1 expression is reduced in adenoid cystic carcinoma, indicating unfavorable prognosis of ACC patients. Its regulation of MMP9 and E-cadherin protein levels suggests a critical therapeutic potential.
authors.affiliation: Department of Stomatology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.forename: Yixi
authors.initials: Y
authors.lastname: Luo
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.forename: Liang
authors.initials: L
authors.lastname: Gu
authors.forename: Shu Chi
authors.initials: SC
authors.lastname: Xia
authors.forename: Youcheng
authors.initials: Y
authors.lastname: Yu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis*; D000328:Adult; D015820:Cadherins / Q000378:metabolism; D003528:Carcinoma, Adenoid Cystic / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D053208:Kaplan-Meier Estimate; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D016612:Paraffin Embedding; D016601:RNA-Binding Proteins / Q000096:biosynthesis*; D012468:Salivary Gland Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology*; D018709:Statistics, Nonparametric
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015820:Cadherins; C101633:PA2G4 protein, human; D016601:RNA-Binding Proteins; D018799:Intercellular Adhesion Molecule-1; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9