HIV/AIDS and kidney transplant patients are at much greater risk of contracting 20 different types of cancer than the general population, according to a land mark paper in The Lancet.
The research, which is led by Professor Andrew Grulich from the University of New South Wales' National Centre in HIV Epidemiology and Clinical Research (NCHECR), suggests that immune deficiency - which is common to the two groups - is responsible for the increased risk.
The paper is the first in the world to compare cancer rates between these populations.
HIV/AIDS patients are 11 times more likely to develop Hodgkin's lymphoma - a cancer associated with Epstein Barr Virus - while there is almost four times the risk for those who have a transplant.
There are a number of cancers associated with human papilloma virus, from cervical cancer to cancers of the mouth, penis and anus. In both these populations, all of these cancers were significantly increased.
"The only thing that people with AIDS and transplant recipients share is immune deficiency, otherwise their risk factors for cancer differ markedly," said the lead author, Professor Grulich, of the paper, which has been selected for editorial comment in the journal.
"In other cancers, which are not linked with viruses, such as breast and prostate cancer, both groups had similar rates to the general population," he said.
"Until now, the accepted wisdom was that there were only three cancers associated with HIV - this paper finds that it is more like 20."
One of those three cancers which was already known to be linked with HIV is Kaposi's sarcoma. In that population, there is a 3,640-fold increased likelihood for patients to develop the disease. This research shows that there is also a marked increase in transplant patients - they are 208 times more likely to develop the cancer than the general population.
Professor Grulich suggests the results could have implications for the way HIV/AIDS patients are treated.
"This evidence suggests that immune deficiency is associated with risk of cancer and this suggests we need to maintain people's immune systems at a higher level - and that might mean putting HIV patients on anti-retroviral drugs earlier than is currently the case," he said.
The researchers now plan to look at cancer rates in those with congenital immune deficiency and people who have received other transplanted organs.
Contact details: Professor Andrew Grulich, 0414 385 317; Susi Hamilton, UNSW Media unit, 9385 1583 or 0422 934 024