Cancer, Human Evolution, Testosterone, and Metformin
Copyright 2012, James Michael Howard, Fayetteville, Arkansas, U.S.A.
Metformin has been found to reduce cancer in a number of studies. Recently, Algire, et al., suggest "Our results reveal previously unrecognized inhibitory effects of metformin on ROS production and somatic cell mutation, providing a novel mechanism for the reduction in cancer risk reported to be associated with exposure to this drug." Cancer Prevention Research 2012: "Metformin reduces endogenous reactive oxygen species and associated DNA damage." That is, Algire, et al., suggest metformin reduces mutations in cells that may cause cancer.
I suggest that the basic mechanism by which metformin decreases cancer is reduced testosterone. A number of studies show that metformin reduces testosterone.
It is my hypothesis that human evolution resulted from selection for testosterone: "Androgens in Human Evolution," Rivista di Biologia / Biology Forum 2001; 94: 345-362. (If your library does not subscribe to "Rivista ... ," you may read this at: http://www.anthropogeny.com/Androgens%20in%20Human%20Evolution.htm . If you do not want to bother to visit this website, please, at least, note the chart from "General and Comparative Endocrinology" of 2003 which directly supports my explanation of human evolution. You may see the chart by going to the link above.)
It is also my hypothesis of 1994 that increased testosterone increases breast cancer, as well as other cancers, (International Journal of Cancer 2005; 115: 497). In my paper of 1994, I suggest it is our increase in testosterone that causes so much cancer. Cancer in humans is much higher in humans compared to the great apes, which do not produce as much testosterone as humans.
I have considered the impact of increased testosterone on mutations in human evolution in 2002: “Mutations, Testosterone, and Human Evolution.” I think our increased testosterone has stimulated our evolution as well as increased our rates of cancer as well as our mutation rates. I suggest Algire, et al., may support my explanation of cancer.