The Four Molecular Classifications of Gastric Adenocarcinoma: A Review of What We Already Know

Abstract

Gabriel Oliveira Dos Santos, Warley Abreu Nunes, Guilherme Andrade Pellissari, Beatriz Sayuri Ishigaki, Pedro Jose Silva Dos Santos, Emilia Scalco Wachter, Adriana Vial Roehe

Gastric malignancies are currently the third leading cause of cancer-related deaths worldwide. Several classification proposals have been made, initially morphological and currently molecular, with the latter aiming to integrate neoplasms with specific molecular and prognostic characteristics. The most recent and widely disseminated one subdivides them into 4 groups: EBV-positive adenocarcinomas; adenocarcinomas with high microsatellite instability; adenocarcinomas with chromosomal instability; and genomically stable adenocarcinomas. The objective is to achieve better classification and consequently greater definition in risk stratification, treatment, and prognosis. The high costs involved in the genomic and molecular analyses necessary for complete molecular classification, especially for chromosomally unstable and genomically stable subtypes, are certainly still limiting factors for the dissemination of molecular classification and the understanding of the expected behavior for each of them.