Why does cancer metastasize?

The metastasis of cancer cells may be due to awakening dormant transcription factors related to embryonic development in the body. Generally speaking, the metastasis of cancer cells can be divided into several stages: the first stage is called invasion. At this stage, the epithelial cells of cancer cells will loosen the connection between cancer cells, making cancer cells "free" and transfer to other places. The second stage is called infiltration, in which cancer cells enter the circulatory system through the endothelium of blood vessels or lymphatic vessels. The third stage is called extravasation. At this stage, survivors baptized by the circulatory system will pass through the endothelial cells of microvessels and reach other tissues. The final stage is that these cancer cells migrate to the new world, thrive in other tissues and form metastatic malignant tumors. Although some genes related to metastasis have been revealed, most studies are about injecting cancer cells into the circulatory system, so there is a lack of gene research related to invasion and infiltration. The research team led by Robert Weinberg of the whitehead Institute of Massachusetts Institute of Technology recently published research results related to the early stage of cancer metastasis. First, they used the popular microarray technology to analyze the gene expression of metastatic mouse breast cancer cells, and found an important transcription factor: Twist. This transcription factor is responsible for triggering cell movement and tissue reorganization in some processes of embryonic development. When the tumor metastasizes, similar cell movement and tissue remodeling can also occur. They found that Twist can make the cell adhesion regulated by E(E-cadherin) fail, resulting in epithelial-mesenchymal transition (EMT) of epithelial cells. Moreover, the metastasis degree of cancer cells whose Twist expression is blocked will be reduced, and the number of cancer cells in the circulatory system will also be reduced. In addition, Twist was also observed to inhibit the expression of E- cadherin in invasive lobular carcinoma of human breast cancer. Therefore, Weinberg and others speculate that the reason why cancer cells can metastasize may be because they wake up the genes that have been sleeping for a long time in the body and are responsible for early embryonic development, thus starting the relevant procedures, thus gaining the terrible ability of metastasis. In the future, drugs may be developed to inhibit the expression of Twist and other genes and avoid tumor metastasis. Or by screening these genes, we can find the future trend of the tumor early and give corresponding treatment. Perhaps in the future, cancer will not be such a terrible scourge, but it may not become another chronic disease.