title: In silico analysis and immunohistochemical characterization of NaPi2b protein expression in ovarian carcinoma with monoclonal antibody Mx35.
abstract: BACKGROUND
  Ovarian adenocarcinoma is frequently detected at the late stage, when therapy efficacy is limited and death occurs in up to 50% of the cases. A potential novel treatment for this disease is a monoclonal antibody that recognizes phosphate transporter sodium-dependent phosphate transporter protein 2b (NaPi2b).
  
  
  METHODS
  To better understand the expression of this protein in different histologic types of ovarian carcinomas, we immunostained 50 tumor samples with anti-NaPi2b monoclonal antibody MX35 and, in parallel, we assessed the expression of the gene encoding NaPi2b (SCL34A2) by in silico analysis of microarray data.
  
  
  RESULTS
  Both approaches detected higher expression of NaPi2b (SCL34A2) in ovarian carcinoma than in normal tissue. Moreover, a comprehensive analysis indicates that SCL34A2 is the only gene of the several phosphate transporters genes whose expression differentiates normal from carcinoma samples, suggesting it might exert a major role in ovarian carcinomas. Immunohistochemical and mRNA expression data have also shown that 2 histologic subtypes of ovarian carcinoma express particularly high levels of NaPi2b: serous and clear cell adenocarcinomas. Serous adenocarcinomas are the most frequent, contrasting with clear cell carcinomas, rare, and with worse prognosis.
  
  
  CONCLUSIONS
  This identification of subgroups of patients expressing NaPi2b may be important in selecting cohorts who most likely should be included in future clinical trials, as a recently generated humanized version of MX35 has been developed.
authors.affiliation: LIM14 – Department of Pathology, Faculdade de Medicina da Universidade de São Paulo, Brazil. iberesoares@lim14.fm.usp.br
authors.forename: Ibere Cauduro
authors.initials: IC
authors.lastname: Soares
authors.forename: Kleber
authors.initials: K
authors.lastname: Simões
authors.forename: Jorge Estefano Santana
authors.initials: JE
authors.lastname: de Souza
authors.forename: Oswaldo Keith
authors.initials: OK
authors.lastname: Okamoto
authors.forename: Alda
authors.initials: A
authors.lastname: Wakamatsu
authors.forename: Maria  Carolina
authors.initials: M
authors.lastname: Tuma
authors.forename: Gerd
authors.initials: G
authors.lastname: Ritter
authors.forename: Venancio Avancini Ferreira
authors.initials: VA
authors.lastname: Alves
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000378:metabolism / Q000473:pathology; D000368:Aged; D058846:Antibodies, Monoclonal, Murine-Derived / Q000737:chemistry*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000737:chemistry; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D009363:Neoplasm Proteins; C493557:SLC34A2 protein, human; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb