Question

Do tumor cells stop at every possible vasculature along the blood pathway to see if they can survive? Or, are there specific mechanisms or signaling pathways that let a cancer cell know if they would be successful before they even stop? I

Answer 1

That is an interesting question and the answer to that whether cancerous cells need to check along the blood vessels for adequate nutrient and oxygen supply would be no, but that doesn't mean a cancerous cell is impervious to the lack of oxygen and nutrient. It simply implies that it has an ability to promote angiogenesis anywhere in the body; kind of like a bully who takes what he wants. But to the mechanism or signaling pathways that lead to angiogenesis is a plethora of processes including upregulation of angiogenic activators and also downregulation of inhibitors. More than a dozen different proteins have been identified as angiogenic activators, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiogenin, transforming growth factor (TGF)-α, TGF-β, tumor necrosis factor (TNF)-α, platelet-derived endothelial growth factor, granulocyte colony-stimulating factor, placental growth factor, interleukin-8, hepatocyte growth factor, and epidermal growth factor.
Cancer cells can produce these activators and force endothelial cells to do his bidding by secreting VEGF onto the surrounding tissue. Not only this but cancer cells downregulate the negative regulators including angiostatin, endostatin, interferon, platelet factor 4, thrombospondin.
This is usually how cancer cells regulate angiogenesis in the body and the reason behind how they metastasize.

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