title: Generation of PRL-3- and PRL-1-specific monoclonal antibodies as potential diagnostic markers for cancer metastases.
abstract: OBJECTIVE
  The PRL-3 mRNA is consistently elevated in metastatic samples derived from colorectal cancers. We sought to generate a specific PRL-3 monoclonal antibody (mAb) that might serve as a potential diagnostic marker for colorectal cancer metastasis.
  
  
  METHODS
  PRL-3 is one of three members (PRL-1, PRL-2, and PRL-3) in a unique protein-tyrosine phosphatase family. Because the three PRLs are 76% to 87% identical in their amino acid sequences, it poses a great challenge to obtain mAbs that are specific for respective phosphatase of regenerating liver (PRL) but not for the other two in the family. We screened over 1,400 hybridoma clones to generate mAbs specific to each PRL member.
  
  
  RESULTS
  We obtained two hybridoma clones specifically against PRL-3 and another two clones specifically against PRL-1. These antibodies had been evaluated by several critical tests to show their own specificities and applications. Most importantly, the PRL-3 mAbs were assessed on 282 human colorectal tissue samples (121 normal, 17 adenomas, and 144 adenocarcinomas). PRL-3 protein was detected in 11% of adenocarcinoma samples. The PRL-3- and PRL-1-specific mAbs were further examined on 204 human multiple cancer tissues. The differential expressions of PRL-3 and PRL-1 confirmed the mAbs' specificity.
  
  
  CONCLUSIONS
  Using several approaches, we show that PRL-3- or PRL-1-specific mAbs react only to their respective antigen. The expression of PRL-3 in >10% of primary colorectal cancer samples indicates that PRL-3 may prime the metastatic process. These mAbs will be useful as markers in clinical diagnosis for assessing tumor aggressiveness.
authors.affiliation: Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Ke
authors.initials: K
authors.lastname: Guo
authors.forename: Vicki Wei Chyi
authors.initials: VW
authors.lastname: Koh
authors.forename: Jing Ping
authors.initials: JP
authors.lastname: Tang
authors.forename: Bin Qi
authors.initials: BQ
authors.lastname: Gan
authors.forename: Hong
authors.initials: H
authors.lastname: Shi
authors.forename: Hui Xiang
authors.initials: HX
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Zeng
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000556:secondary; D000236:Adenoma / Q000175:diagnosis*; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000276:immunology*; D015153:Blotting, Western; D018797:Cell Cycle Proteins; D003106:Colon / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006825:Hybridomas; D017874:Immediate-Early Proteins / Q000276:immunology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011379:Prognosis; D017027:Protein Tyrosine Phosphatases / Q000276:immunology*; D012007:Rectum / Q000378:metabolism; D012680:Sensitivity and Specificity; D017386:Sequence Homology, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D017874:Immediate-Early Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C490198:PTP4A1 protein, human; C484730:PTP4A3 protein, human; D017027:Protein Tyrosine Phosphatases