Tumor microenvironment: a new treatment target for cancer.

Recent advances in cancer therapy encounter a bottleneck. Relapsing/recurrent disease almost always developed eventually with resistance to the initially effective drugs. Tumor microenvironment has been gradually recognized as a key contributor for cancer progression, epithelial-mesenchymal transition of the cancer cells, angiogenesis, cancer metastasis, and development of drug resistance, while dysregulated immune responses and interactions between various components in the microenvironment all play important roles. Future development of anticancer treatment should take tumor microenvironment into consideration. Besides, we also discuss the limitations of current pre-clinical testing models that mainly come from the impossibility in simulating all detailed carcinogenic mechanisms in human, especially failure to create the same tumor microenvironment. With the cumulating knowledge about tumor microenvironment, the design of a novel anticancer therapy may be facilitated and may have better chance for success in cancer eradication.