JAK2 and gastric cancer: Zhao and co-workers reported that TAMs isolated from gastric cancer tissues predominantly display an M2 phenotype (Li et al., 2019) and gastric cancer-derived mesenchymal stromal cells promote metastasis and epithelial-mesenchymal transition (EMT) by triggering M2 TAM polarization through the IL-6/IL-8-JAK2-STAT3 signaling pathway.