| According to the National Cancer Institute, solid tumors cannot grow beyond the size of a pinhead, that is, 1-2 cubic mm, without inducing the formation of new blood vessels to supply the nutritional needs of the tumor. Since rapid vascularization and tumor growth appear to occur concurrently, interrupting the vascular growth cycle is paramount to overcoming the malignancy. Tumor angiogenesis results from a cascade of molecular and cellular events, usually initiated by the release of angiogenic growth factors. At a critical phase in the growth of a tumor, the tumor sends out signals to nearby endothelial cells to activate new blood vessel growth. The pro-angiogenic growth factors diffuse in the direction of preexisting blood vessels, encouraging development (Folkman 1992 b; Folkman et al. 1992 a). Various agents are known to activate endothelial cell growth, including angiogenin, estrogen, interleukin-8, fibroblast growth factors (both acidic and basic), prostaglandin E2, tumor necrosis factor, granulocyte colony-stimulating factor, and VEGF. VEGF and basic fibroblast growth factors are expressed by many tumors and appear particularly important to tumor development and angiogenesis (NIH/NCI 1998) A number of substances from orthodox and natural pharmacology (angiostatin, endostatin, interferons, interleukin-2, curcumin, green tea, lactoferrin, N-acetyl-cysteine (NAC), resveratrol, grape seed-skin extract, retinoic acid (vitamin A), and vitamin D) are antiangiogenic in nature. Endostatin, a fragment of collagen XVIII, and angiostatin, a fragment of plasminogen involved in the coagulation process, have produced remarkable results in animal models. | Blood Test Super Sale on now! During our annual Blood Test Super Sale, members save up to 80% compared to the retail prices charged by other blood testing labs. For the first time, Life Extension members can obtain the comprehensive Male or Female Blood Test Panels for only $198. These same tests can cost over $1,000 at other laboratories, but are being offered to members at this previously unheard of low price until June 2, 2008. In addition, Life Extension is now offering a vitamin D blood test for only $25) when you purchase a comprehensive Male or Female Panel that is 50% below our low retail price, and about 80% below what commercial labs charge. Since vitamin D deficiency occurs most commonly during the winter months when the majority of Americans do not receive adequate sunlight, spring is the ideal time to check your vitamin D status. |
