“HIV protects against cancer and cannot cause AIDS” (2009/12/01) reported on a paper presented at the Annual Congress of the Italian Association of Cell Cultures by Ruggiero, Pacini, et al.: the HIV protein, VpR, induces selective killing of rapidly dividing cancer cells.
This pointed to a possibly symbiotic relation between HIV and the human genome, the anti-cancer action of HIV causing it to be selectively favored by evolutionary processes.
That evolution of mechanisms for warding off cancer may have been crucial elements in the evolution of higher organisms had been postulated also by James Graham.
Now there comes further support for this from an independent source. Hessol et al., “HIV tropism and decreased risk of breast cancer” [PLoS One, 16 December 2010, 5(12):e14349], found that “breast cancer risk was significantly lower for women with human immunodeficiency virus (HIV) infection compared to the general population. This deficit in HIV-associated breast cancer could not be attributed to differences in survival, immune deficiency, childbearing or other breast cancer risk factors” . It seems that “Low breast cancer risk with HIV is specifically linked to CXCR4-using variants of HIV”.
This is a different mechanism than that found by Ruggiero et al. Perhaps that explains why Hessol et al. don’t cite them or Graham, but a more probable reason is the explosive growth of publications about cancer and HIV, which makes it all but impossible to remain aware of all potentially relevant research.