Further, in the GS subtype, the TCGA study showed that diffuse histology, mutations in the E-cadherin gene (CDH1), mutations in the Ras Homolog Family Member A (RhoA) gene—a GTPase family involved in several biological processes; and fusions involving Claudin-18 (CLDN18)—a component of tight junctions; were enriched in this subtype of GC [4,10]. Here, CLDN18 is linked to gastric cancer.