Fig. 2
Lymphocytes and immune checkpoints in the gastric cancer immunoregulation. CSC, cancer stem cell; PCC, progenitor cancer cell; MSC, mesenchymal stem cell; Neu, neutrophil; NK, natural killer lymphocyte; VEGF, vascular endothelial growth factor; PGE2, prostaglandin E2; MIP-2, macrophage inflammatory protein-2. The interaction between MSCs and PCCs promotes lymphocyte differentiation towards the Th17 phenotype. Furthermore, interaction between MSCs and CSCs favors a Treg phenotype. Differentiation of both, Treg and Th17 lymphocytes, into an intermediate IL-17+FOXP3+ phenotype is possible, and the presence of this population has been shown to promote stemness in cancer cells. Expression of immune checkpoints can favor immune evasion in tumors, however, it can also stimulate stemness characteristics