S100A4 and breast cancer: Downregulation of CAV1 in breast cancer promotes tumor relapse, drug resistance, and poor outcome [52,53], and has been related to the increased expression of several growth factors and regulators, like stromal cell-derived factor-1 (SDF-1), epidermal growth factor (EGF), and fibroblast-specific protein-1 (FSP-1) [54].