A Single-Center Comparative Study of the c-MET Immunohistochemistry SP44 and LBP4 Assays in Chinese Non-Small Cell Lung Cancer (NSCLC) Cohort.

Abstract

c-MET is a promising therapeutic target in non-small cell lung cancer (NSCLC). This necessitates accurate detection of c-MET aberrations for effective c-MET tyrosine kinase inhibitor (TKI) therapy. Immunohistochemistry (IHC) is widely used to identify c-MET overexpression. SP44 is the most common antibody for c-MET IHC, but LBP4, a novel monoclonal antibody, offers a cost-effective alternative. This study compares LBP4 and SP44 to enhance c-MET IHC accessibility and identify NSCLC patients who may benefit from c-MET TKI therapy. LBP4 and SP44 antibodies were compared in 238 NSCLC cases from West China Hospital, with 73 specimens further analyzed for secondary antibody consistency (Ultraview vs. Optiview). c-MET IHC results were blindly evaluated by 3 pathologists. In addition, overall survival (OS) and progression-free survival (PFS) were analyzed in 51 savolitinib-treated patients. LBP4 and SP44 antibodies showed high consistency (93.7%, κ=0.908). SP44 demonstrated 97.26% concordance between Ultraview and Optiview (κ=0.9559), while LBP4 achieved 95% concordance (κ=1.0). In savolitinib-treated patients, c-MET IHC 2+/3+ cases had significantly higher OS than IHC 1+ (P=0.0035). LBP4 shows strong concordance with SP44, providing a cost-effective alternative for c-MET IHC. Ultraview secondary antibody performs comparably to Optiview. LBP4 combined with Ultraview effectively identifies NSCLC patients likely to benefit from c-MET TKI therapy, supporting c-MET IHC as a reliable screening tool and promoting its clinical application.