Evaluation of PD-L1 expression in gastric cancer: correlation between the primary site and lymph node metastasis

• Grant number: 20/02880-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2020
• End date: July 31, 2021
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Marcus Fernando Kodama Pertille Ramos
• Grantee: Brendha Cação Coimbra
• Host Institution: Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (ICESP). Coordenadoria de Serviços de Saúde (CSS). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Gastric cancer is a globally distributed disease, being the 5th most common cause of cancer, with estimates of 21,290 new cases of gastric cancer in 2018 in Brazil alone. Lauren's histological type and the TNM stage system are the main prognostic factors used in current clinical practice, however they still prove to be insufficient to predict individual disease progression. In recent years, the molecular classification of tumors has made it possible to identify new prognostic biomarkers and therapeutic targets, such as the PD-1 / PD-L1 and PD-L2 pathways. In this way, the use of immunotherapy as an emerging therapeutic target in the regulation of the anti-tumor response stands out. The expression of PD-L1 in tumor cells has recently been validated as a predictive marker of response to anti-PD-1 or anti-PD-L1 immunotherapy in gastric cancer. Clinical studies report that both patients with positive PD-L1 tumors and some specific groups of patients with negative PD-L1 tumors may benefit from treatment with anti-PD-1 / PD-L1. However, few studies have examined the prognostic value of PD-L1 expression at metastatic sites, which are believed to have greater marker expression. Still, there are no consistent data that relate the expression of PD-L1 between primary sites and lymph node metastases, which could provide information with potential assistance in the development of treatment alternatives capable of providing additional benefits. In this scenario, the current study seeks to clarify the relationship between the expression of PD-L1 in primary tumors and in lymph node metastases, investigating particularly the degree of expression of PD-L1 in these two sites, the accuracy of the evaluation for each one by immunohistochemistry , and relating these data to prognostic factors and survival.