 This is the first in a three-part video series on cancer metastasis. I'll look at what dietary components might contribute to the spread of cancer, and what dietary interventions, including specific foods, that may lessen the risk of cancer spreading and thereby increase the chance of survival. Let's go find out. Metastasis formation is the leading cause of death in cancer patients. That's how most people die of cancer. It's not the primary tumor, but the cancer spreading through the body. It's estimated that metastasis is responsible for 90% of cancer deaths, with little progress made in stopping the spread, despite our modern medical armamentarium. In fact, we can sometimes make it worse. Therapy-induced metastasis. All the typical cancer treatments—radiation, chemotherapy, surgery— even just poking the tumors with fine needle biopsies have the potential to contribute to the problem. I mean, you can imagine how cutting around a tumor, severing the blood vessels, might lead to the migration of residual tumor cells. But why chemotherapy? How might chemo exacerbate metastasis? Despite reducing the size of primary tumors, chemotherapy can change the surrounding tissues, resulting in an increased escape of cancer cells into the bloodstream. Sometimes a chemotherapy radiation are entirely justified, but sometimes these treatments can make things worse, if only we had a way to treat the cause of the cancer spreading. The development of anti-metastatic therapies has been hampered by the fact that we haven't been able to identify the cells that initiate metastasis, but then this landmark study was published. Researchers found a subpopulation of human cancer cells unique in their ability to initiate metastasis, all expressing high levels of a fat receptor known as CD36, dubbed the fat controller. It turns out, pulmitic acid or high-fat diet specifically boosts the metastatic potential of these cancer cells. Amortified pulmitic acid, although originally discovered in palm oil, it's most concentrated in meat and dairy. Emerging evidence shows that pulmitic acid serves as a signaling molecule regulating the progression and development of many diseases at the molecular level, and that's the saturated fat that is recognized by the CD36 receptor on the cancer cells. And we know that's to blame, because if you block the CD36 receptor, you block the metastasis. Now this was for human cancer, however it was a human cancer implanted into mice. But clinically, meaning in cancer patients, the presence of these CD36-studded metastasis-initiating cells does indeed correlate with a poor prognosis. For example, CD36 appears to drive the progression of brain tumors. If you look at the survival curves, tumors with tumors with less CD36 expression lived significantly longer. The same with breast cancer mortality. No surprise, since CD36 appears to play a critical role in the proliferation, migration, and growth of breast cancer cells. Inhibit CD36, and you can inhibit the migration and invasion of breast cancer cells. Cancer cell migration and invasion before and after CD36 inhibition. And not just in human melanoma and breast cancer-derived tumors. Now we suspect that CD36 drives ovarian cancer progression and metastasis, too, since we can inhibit ovarian cancer cell invasion and migration, and block both lymph node and blood-borne metastases by blocking CD36. We see the same kind of effect with prostate cancer. That's the uptake of fat by prostate cancer cells, and you can suppress the tumor. This was all studied with receptor-blocking drugs and antibodies in a laboratory setting, though. If these metastasis-initiating cancer cells particularly rely on dietary fat to promote the spread of cancer, why not just block the dietary fat in the first place? Cancer cells love fat and cholesterol. The reason why fat metabolism may fuel cancer spread is because there's so much energy stored in fat. Hence, metastatic cells might take advantage of this feature to obtain the high amount of energy that is likely to be required for them to anchor and set up shop throughout the body. The time when sugar was considered as a major, if not only fuel, to support cancer cell proliferation is over. There appears to be a fatter way to metastasize. No wonder high-fat diets may play a crucial role in increasing the risk of different cancer types, including several advanced cancers. Okay, if dietary fat may be greasing the wheels of the cancer machine, might there be specific dietary regimens we could use to starve cancers of dietary fat? You don't know until you put it to the test, which we'll cover next.