VEGFA and breast cancer: Keyword co-occurrence and co-citation clustering analysis revealed that studies of MSC-EVs covered cellular origin (bone marrow mesenchymal stem cell, adipose-derived mesenchymal stem cell), injurious diseases (spinal cord injury, acute lung injury, ischemia/reperfusion injury, acute kidney injury, traumatic brain injury), tumor (breast cancer, tumor microenvironment), biological processes (drug delivery system, angiogenesis, inflammation, proliferation, differentiation, senescence), and molecular mechanisms (signaling pathway, signal transduction, oxidative stress, VEGF, TGF β).