BMP4 and gastric cancer: They reported that KLF2+ epithelial cells recruited by plasma cells in diffuse‐type GC, IgA+ plasma cells, and SDC2+ carcinoma‐associated fibroblasts (CAFs) are enriched in precancerous lesions and GC, that high expression of epithelial‐myofibroblast transformation is associated with poor clinical prognosis, and that PDGFRA+BMP4+WNT5A+ fibroblasts play an important role in the IM.