POSTN and neoplasm: Further, it has also been reported that the dormant niche and the micrometastatic outgrowths are promoted by different kinds of vasculature systems, where the ECs within the stable microvasculature secrete thrombospondin-1 that promotes the dormancy of the tumour cells, while the sprouting neovasculature secretes periostin and transforming growth factor-β1 (TGF-β1) favouring proliferation of the metastatic tumour cells [66].