Inflammation, Macrophage in Cancer Progression and Chinese Herbal Treatment

Inflammation is associated with cancer development, and has been recognized as the seventh hallmarks of the cancer. Cancer-related inflammation can be activated by genetic or epigenetic changes in cancer cells (intrinsic pathway) or mediated by tumor-infiltrating immune cells (extrinsic pathway). Immune cells involved in cancer-related inflammation mainly including tumor-associated macrophages or M2 macrophages, neutrophils, dendritic cells, mast cells, and lymphocytes. As major players of the cancer-related inflammation, M2 macrophages, secreting various of growth factors, immunomodulatory cytokines and matrix metalloproteinases, participate in remodeling of extracellular matrix, contribute to cancer invasion and metastasis, angiogenesis, and inhibit anti-cancer immunity. Inflammation has been considered as an important target for cancer therapy. Some Chinese herbal ingredients have been confirmed to be effective in inhibit inflammation related gene expression in cancer cells, such as COX-2 and NF-B. However, there is a shortage of study on Chinese herb or herbal ingredient against extrinsic cancer inflammation, especially in tumor-associated macrophages. Related studies may provide new insight into cancer treatment.