Department of Surgery, Maastricht University Medical Center, The Netherlands.
Clin Nutr. 2013 Jun;32(3):460-5. doi: 10.1016/j.clnu.2012.07.010. Epub 2012 Aug 21.
Cancer growth is characterized by proliferation of tumor cells in conjunction with invasion of all different immune cells that also invade healing wounds. This inflammatory response is necessary for cell proliferation but a second purpose of the inflammatory process is so that a low Th1/Th2 ratio is present with overexpression of IL-10, TGF-β and IFN-γ. Down regulation of NO activity also shifts the balance between M1 and M2 macrophages. Both aspects allow the antigenous nature of the tumor to escape anti-tumor effects of the host. Support for this view comes from observations in pregnancy in which the placenta exhibits identical immune responses and downregulation of NO production to allow trophoblast cells to invade the uterine tissues without being rejected. Cell proliferation requires a metabolic set-up in which the organism produces adequate substrate for growth. This also bears the characteristics of a systemic inflammatory response delivering a similar substrate mix required for cancer and fetal growth. This arrangement is clearly beneficial in pregnancy and therefore supports the view that cancer growth is facilitated by the organism: the cancerous tumor elicits an immunological response opposing anti-tumor effects and induces the host to produce building blocks for growth.
癌症的生长特征是肿瘤细胞的增殖，同时伴随着所有不同的免疫细胞的浸润，这些免疫细胞也会浸润正在愈合的伤口。这种炎症反应对于细胞增殖是必要的，但炎症过程的第二个目的是使 Th1/Th2 比值降低，IL-10、TGF-β和 IFN-γ表达过度。NO 活性的下调也会改变 M1 和 M2 巨噬细胞之间的平衡。这两个方面都使肿瘤的抗原性质逃避宿主的抗肿瘤作用。这一观点得到了妊娠观察的支持，在妊娠中，胎盘表现出相同的免疫反应，并下调 NO 的产生，以使滋养细胞能够侵入子宫组织而不被排斥。细胞增殖需要一种代谢机制，使机体产生足够的生长底物。这也具有全身炎症反应的特征，提供了癌症和胎儿生长所需的类似底物混合物。这种安排在妊娠中显然是有益的，因此支持这样一种观点，即癌症的生长是由机体促进的：癌变肿瘤引发免疫反应，对抗抗肿瘤作用，并诱导宿主产生生长所需的构建块。
