Evaluation of PDL-1 Protein Expression in Tumor Tissues of Patients with Gasteric Cancer

Background and Objective: Nowadays, it has been proven that the immune system plays a major role in the occurrence or treatment of some cancers. The PDL-1 proteins are among the components of the immune system, which are expressed in different body cells, including B cells and T cells. In this regard, the present study was conducted to determine the frequency of PDL-1 protein expression and its relationship with tumor histopathology in patients with gastric cancer. Materials and Methods: In this case series study, 100 patients referred to the Oncology Clinic, located in Imam Khomeini Clinic, Hamadan, Iran, between 2016-2021, with the diagnosis of gastric cancer (confirmed by endoscopic biopsy pathology) were selected. Moreover, their PDL-1 protein expression (with IHC) and its relationship with age, gender, metastasis, stage, and grade of the tumor were evaluated. Results: The average age of patients was 65.53 ± 10.83 years, and 72% were male. The result of PDL-1 protein expression showed that 2 patients were negative, 25 patients were weakly positive and 73 patients were strongly positive. In addition, 69 Out of 100 patients had metastases, 69 cases had high grade and 68 were in stage 4 of the disease. A significant relationship was observed between PDL-1 expression with metastasis, higher grade, and higher stage of the tumor (P<0.05). Conclusion: Most patients with gastric cancer had a strongly positive expression of PDL-1 protein. Expression of PDL-1 was significantly associated with the severity of gastric cancer (e.g., grade, higher stage, and metastasis); therefore, the PDL-1 biomarker could be used as a determinant of gastric cancer severity and prognosis