title: A novel multipurpose monoclonal antibody for evaluating human c-Met expression in preclinical and clinical settings.
abstract: The inappropriate expression of the c-MET cell surface receptor in many human solid tumors necessitates the development of companion diagnostics to identify those patients who could benefit from c-MET targeted therapies. Tumor tissues are formalin fixed and paraffin embedded (FFPE) for histopathologic evaluation, making the development of an antibody against c-MET that accurately and reproducibly detects the protein in FFPE samples an urgent need. We have developed a monoclonal antibody (mAb), designated MET4, from a panel of MET-avid mAbs, based on its specific staining pattern in FFPE preparations. The accuracy of MET4 immunohistochemistry (MET4-IHC) was assessed by comparing MET4-IHC in FFPE cell pellets with immunoblotting analysis. The technical reproducibility of MET4-IHC possessed a percentage coefficient of variability of 6.25% in intra-assay and interassay testing. Comparison with other commercial c-MET antibody detection reagents demonstrated equal specificity and increased sensitivity for c-MET detection in prostate tissues. In cohorts of ovarian cancers and gliomas, MET4 reacted with ovarian cancers of all histologic subtypes (strong staining in 25%) and with 63% of gliomas. In addition, MET4 bound c-MET on the surfaces of cultured human cancer cells and tumor xenografts. In summary, the MET4 mAb accurately and reproducibly measures c-MET expression by IHC in FFPE tissues and can be used for molecular imaging in vivo. These properties encourage further development of MET4 as a multipurpose molecular diagnostics reagent to help to guide appropriate selection of patients being considered for treatment with c-MET-antagonistic drugs.
authors.affiliation: Department of Pathology, University of Washington Medical Center, NE Pacific, Seattle, WA, USA.
authors.forename: Beatrice S
authors.initials: BS
authors.lastname: Knudsen
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: James
authors.initials: J
authors.lastname: Resau
authors.forename: Sandra
authors.initials: S
authors.lastname: Cottingham
authors.forename: Ermanno
authors.initials: E
authors.lastname: Gherardi
authors.forename: Eric
authors.initials: E
authors.lastname: Xu
authors.forename: Bree
authors.initials: B
authors.lastname: Berghuis
authors.forename: Jennifer
authors.initials: J
authors.lastname: Daugherty
authors.forename: Tessa
authors.initials: T
authors.lastname: Grabinski
authors.forename: Jose
authors.initials: J
authors.lastname: Toro
authors.forename: Troy
authors.initials: T
authors.lastname: Giambernardi
authors.forename: R Scot
authors.initials: RS
authors.lastname: Skinner
authors.forename: Milton
authors.initials: M
authors.lastname: Gross
authors.forename: Eric
authors.initials: E
authors.lastname: Hudson
authors.forename: Eric
authors.initials: E
authors.lastname: Kort
authors.forename: Ernst
authors.initials: E
authors.lastname: Lengyel
authors.forename: Aviva
authors.initials: A
authors.lastname: Ventura
authors.forename: Richard A
authors.initials: RA
authors.lastname: West
authors.forename: Qian
authors.initials: Q
authors.lastname: Xie
authors.forename: Rick
authors.initials: R
authors.lastname: Hay
authors.forename: George
authors.initials: G
authors.lastname: Vande Woude
authors.forename: Brian
authors.initials: B
authors.lastname: Cao
mesh_terms: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000592:standards; D005260:Female; D005557:Formaldehyde; D005910:Glioma; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009369:Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology*; D010051:Ovarian Neoplasms; D016612:Paraffin Embedding; D019859:Proto-Oncogene Proteins c-met / Q000032:analysis*; D016707:Tissue Fixation
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D005557:Formaldehyde; D019859:Proto-Oncogene Proteins c-met