Japan’s low mortality from prostate cancer, and their low meat consumption, with the high prostate cancer mortality in the US, which has a higher meat consumption. But Argentina and Mexico’s prostate cancer mortality ranks very favorably with Japan’s.
If meat consumption in the US contributes to the very high cancer rate, it clearly isn’t the quantity of meat consumed, but rather the quality of the meat.
Although the diffusion of these stimulating factors from stressed tissues normally functions to accelerate healing and tissue regeneration, under less optimal conditions they are undoubtedly important factors in tissue degeneration and tumor formation. For example, the bystander effect (contributing to delayed radiation damage, and producing a field of precancerous changes around a cancer), in which substances diffusing from injured tissues damage surrounding cells, involves disturbances in polyamine metabolism.
The direct, optimal effects of the polyamines are protective, but when excessive, prolonged, or without maintained cellular energy, they become harmful.
The expression of genes involves their physical arrangement and accessibility to enzymes and substrates. The negatively charged nucleic acids are associated with positively charge proteins, the histones. The very small positively charged polyamines can powerfully modify the interactions between histones and DNA. In recent years people have begun to speak of the “histone code,” as a kind of expansion of the idea of the “genetic code.” But the polyamines, produced in response to stress, might be thought of as a complex expansion of the “histone code.”