MMP9 and neoplasm: Adipocyte progenitors (CD45-CD34+) in xenograft and breast cancer models secrete granulocyte-macrophage colony-stimulating factor (GM-CSF) and matrix metalloproteinase 9 (MMP-9), thereby inducing immunosuppression, intratumor vascularization, as well as local and metastatic tumor growth [44].