S100A4 and neoplasm: S100A4 can also be secreted and once extracellular can affect several facets of tumour progression such as angiogenesis, stimulation of cell motility, upregulation of matrix metalloproteinases (MMPs), modulation of tumour-related transcription factors, and potentially as a stromal factor (Ambartsumian et al, 2001; Belot et al, 2002; Schmidt-Hansen et al, 2004a, 2004b).