tumor metastasis is one of the difficult points of tumor research, more than 90% of cancer patients died of tumor metastasis.Metastasis is one of the characteristics of a malignant tumor cell difference between normal cells and tumor cell metastasis ability is different, even the same kind of tumor cells subgroup with different transfer potential, but also the existence of transfer organ specificity.The occurrence of tumor metastasis is an extremely complex process, involving many factors, including changes in the characteristics of the tumor cells themselves, not only include environmental changes of the patient's own body.
above fluorescence microscopy imaging shows the spread of metastatic tumor, green melanoma cells invading red lymphatic vessels.
used to think that blood vessels (angiogenesis), in the process of tumor growth and evolution plays a key role, but now there is a view of the update is lymphatic generated in the process of tumor proliferation plays a more important role.A large number of clinical pathology data found the lymphatic system is a tumor (especially solid tumor) transfer the original way.
we found with circulating tumor cells in peripheral blood (circulating tumor cells, CTCs), it plays an important role in the process of tumor metastasis and recurrence, part of the primary tumor cells through transformation of epithelial mesenchymal (epithelial mesenchymal transitions, EMT) process so as to obtain high invasive, from primary tissue loss, into the surrounding stroma and enter the blood circulation, become CTCs.
of course, the human body and strong the body's immune system, most CTCs would be killed.But there will be a small number of transfer CTCs survive tend to be very high, and together form the circulating tumor micro switch (circulating tumor microem - boli, CTM).
the surviving CTCs or CTM leave the blood circulation, into the local microenvironment of secondary organs, and evade the host's local nonspecific immune killing effect, under the action of all kinds of growth factors, proliferation growth and ultimately the formation of metastases.This transfer process tend to occur during the late stages of tumour progression.Tumor distant metastasis is likely to have emerged in the early years of tumor development, thus CTCs detection has clinical significance.
number of CTCs have close correlation with survival of cancer patients.
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