MTOR and gastric cancer: To analyse how Semaphorin 6D (SEMA6D) expression and extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathways are activated and how they influence gastric cancer proliferation, migration, and invasion.