Tumor cell metastasis is lymphatic or vascular invasion process. The specific way of metastasis are:
invasion, tumor cells leave the tumor occupied the adjacent normal tissue;
tumor cells into the circulation;
to survive in the circulation;
stranded in the proliferation of capillaries or lymph sinus;
wear clothing with blood bi;
growth in secondary sites, the formation of secondary tumors (metastases), have to be transferred again.
The traditional belief that metastasis from the local start, and then invasion of surrounding tissue, the development of distant metastasis. Not the case now known, there is a wide range of tumor cell heterogeneity, many cancers have distant metastases at the beginning. Thus, although the process of tumor metastasis in recent years, and every step of the details of the mechanism is still the lack of deep understanding, etc., but the anti-metastasis research and development of drugs has attracted wide attention, but also found some resistance to treatment with the transfer of certain drugs . The growth of the tumor cell mass requires adequate blood supply, blood supply is essential, newly formed blood vessels to cancer metastasis provides an ideal channel. Therefore, anti-angiogenesis can inhibit tumor metastasis. Recent discovery, endostatin, angiostatin, MMP inhibitors can inhibit angiogenesis in some areas, resulting in transfer of anti-tumor effect, is in-depth study, has attracted attention.