Systems biology and molecular characterization of subtypes to guide targeted therapies in gastric cancer

Abstract Gastric cancers (GCs) pose a considerable health care burden worldwide. Current treatment options are ineffective. Although patients are treated with identical regimens, response to therapy varies due to both cancer-specific and patient heterogeneity. There is a dire need to classify cancers into homogeneous groups that associate with distinct molecular characteristics and clinical outcomes and allow the development and application of subgroup-guided therapies. Over the years technological advances have helped to chart the genome, the epigenome, and the transcriptome. Systems biology aims to connect these various layers and allow effective molecular classification. In this chapter, we will discuss the genetics of GC, how molecular subtypes are defined by systems biology approaches, current targeted therapies, and how that funnels into strategies for new treatment options.