A novel multipurpose monoclonal antibody for evaluating human c-Met expression in preclinical and clinical settings.
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.
Knudsen
Beatrice S
BS
Department of Pathology, University of Washington Medical Center, NE Pacific, Seattle, WA, USA.
Zhao
Ping
P
Resau
James
J
Cottingham
Sandra
S
Gherardi
Ermanno
E
Xu
Eric
E
Berghuis
Bree
B
Daugherty
Jennifer
J
Grabinski
Tessa
T
Toro
Jose
J
Giambernardi
Troy
T
Skinner
R Scot
RS
Gross
Milton
M
Hudson
Eric
E
Kort
Eric
E
Lengyel
Ernst
E
Ventura
Aviva
A
West
Richard A
RA
Xie
Qian
Q
Hay
Rick
R
Vande Woude
George
G
Cao
Brian
B
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
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D005557:Formaldehyde; D019859:Proto-Oncogene Proteins c-met