Expressão imunofenotípica da PD-1 e PD-L1 em adenocarcinoma gástrico de pacientes atendidos no Hospital Universitário João de Barros Barreto

Abstract

Gastric cancer is the third leading cause of cancer-related death in both genders, and at an advanced stage the prognosis has been unfavorable. Human tumors are prone to escape from immunovigilance, and one of the axes involved in this scenario is PD-1, a receptor expressed on the surface of cells, and its PD-L1 linker, which have already been detected in samples from gastric adenocarcinoma. This study aimed to characterize the immunophenotypic expression of PD-1 and PD-L1 proteins in tissue adjacent to the tumor, primary gastric adenocarcinoma tissue, associated with clinicopathological and demographic findings from patients attending at University Hospital João de Barros Barreto since 2008 to 2016. We selected 92 samples from patients with gastric adenocarcinoma and 55 tissue samples adjacent to the tumor. Tissue microarrays (TMA) were constructed and automated immunostaining was performed (GX Ventana - Roche ®) for PD-1 and PD-L-1. The immunoreactivity for PD-L1 in tumor cells was observed in 8 cases (8.7%), all of them of intestinal histological type of Láuren and advanced staging, presenting, in the most, grade II of differentiation. Whereas cytoplasmic immunoreactivity for PD-1 in the lymphocyte of the intratumoral microenvironment (TIL) was observed in the cytoplasm and occurred in 64 cases (69.6%), being the majority of intestinal histological type of Láuren, advanced staging and grade II of differentiation. Intratumoral PD-1 positive lymphocytes were observed in a greater number of cases when evaluated intratumoral stroma, as compared to the tumor-associated PD-1 lymphocyte lymphocytes adjacent to the tumor. These data reinforce that patients with gastric adenocarcinoma who features the histopathological characteristics found in predominance for both markers analyzed, may be more likely to activate the PD-1 / PD-L1 pathway and are eligible candidates to use anti-PD-1 monoclonal antibody or anti- PD-L1.