Assessment of the level of PD-L1 protein expression on gastric cancer material using the new clone PBM-1A4 and comparison with clones 22C3, SP142, SP263

Abstract

BACKGROUND: The study of the properties of immunotherapeutic markers is a popular and promising area in oncology. One of the most studied targets of immunotherapy is the ligand of the programmed cell death protein 1 (PD-L1). Currently, diagnostic kits for determining PD-L1 expression in tumors are manufactured overseas. To ensure the technological sovereignty of the Russian Federation in medical technologies, research with a domestic clone of PD-L1 antibodies and comparison of the results with already validated analogs are necessary. AIM: To validate a domestic clone of an antibody to PD-L1 (PBM-1A4) , determine the relationship of the reaction with clinical and morphological parameters, and compare with clones SP142, SP263, and 22C3 in gastric cancer. MATERIALS AND METHODS: Comparative immunohistochemical analyses of different PD-L1 clones were performed on paraffin blocks of gastric adenocarcinoma surgical material from 39 patients who had not received chemotherapy, radiation, or immunotherapy preoperatively. RESULTS: PD-L1 expression detected by the PBM-1A4 antibody clone was present in 46.2% of gastric cancer samples. Among PD-L1(PBM-1A4)-positive tumors, neoplasms of the second macroscopic type according to R. Bormann and tubular adenocarcinomas were significantly predominant. The SP142 clone showed the greatest consistency with PBM-1A4 expression (significant consistency, Cohen’s kappa = 0.67335). CONCLUSION: Compared with the SP142 clone, the PBM-1A4 clone to PD-L1 during immunohistochemical examination on gastric adenocarcinoma material showed a close to identical immunological picture when. The data obtained appear promising for the use of the PBM-1A4 clone in the diagnosis of malignant neoplasms for patients with cancer, taking into account its economic component and accessibility.