COL18A1 and neoplasm: Some studies showed that dormant micrometastases are avascular tumour in which there is a balance between proangiogenic factors (vascular endothelial growth factor (VEGF), PDGR, fibroblast growth factor (FGF), angiopoietin) and anti-angiogenic factors (endostatin, agiostatin, TSP), with a slight prevalence of the latter ones (Figure 2) [16].