The cooked meat carcinogen PhIP found in fried bacon, fish, and chicken may not only trigger cancer and promote tumor growth, but also increase its metastatic potential by increasing its invasiveness.
Images thanks to the National Cancer Institute and U.S. Navy photo by Chief Warrant Officer 4 Seth Rossman via Wikimedia Commons
DNA mutation, then promoting growth, and the third strike is that PhIP then promotes invasiveness of breast cancer cells. The way breast tumors kill is by metastasis, it's got to invade surrounding tissues and organs. The way you test invasiveness is you put cells into what's called an invasion chamber where you put cancer cells on one side of a membrane with tiny pores, those little gray circles. This is the underside of the filter, showing no invasion. But add some estrogen and you can see a few cells peeking through. Add some PhIP and they really start going on the move. More invasion-promoting that straight estrogen. They conclude that “in addition to its well characterized, genotoxic potential, PhIP is potently estrogenic, is capable of powerful hormonal activity and is able to potently stimulate breast cancer cells to invade through a membrane model. This finding that PhIP is able to exert this pro-invasive appearance in breast cancer cells at such low concentrations is remarkable. The genetic toxicology of the compound coupled to its ability to enhance cell proliferation and invasion indicates that PhIP can act not only to initiate the carcinogenic process, but also to promote it." The problem is, they say, that "Exposure to PhIP is difficult to avoid because of its presence in many commonly consumed cooked meats, particularly chicken, beef and fish." But if you're able to somehow dodge those meats, and don't suck on a cigarette, tailpipe, or incinerator smokestack, maybe it's not so difficult to avoid after all.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.
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The "difficult to avoid" line reminds me of the cop-out in the Dead Meat Bacteria Endotoxemia video. This is the second of a four-part video series on heterocyclic amines, carcinogens such as PhIP that are formed when meat is cooked. In my last video Estrogenic Cooked Meat Carcinogens, I noted that in addition to being able to cause the initial DNA damage that may trigger breast cancer, these chemicals may act as potent estrogens, promoting the growth of such tumors as well.
The growth hormone IGF-1 may also promote tumor progression and invasion (see IGF-1 as One-Stop Cancer Shop). IGF-1 is released by our liver in response to animal protein consumption (why? See Higher Quality May Mean Higher Risk.)
In the next video Reducing Cancer Risk In Meateaters, I'll note some ways for non-vegetarians to mediate their risk.
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