AIDS sufferers and transplant patients are at a much higher risk than the general population of developing a range of cancers, according to an Australian research released yesterday.

The new study, published in The Lancet medical journal, suggests a link between a depleted immune system and 20 different types of cancerand could be a breakthrough in the understanding of the causes of the malignancies.

Lead researcher at Sydney's University of New South Wales, Professor Andrew Grulich said the research looked at two groups -those infected with HIV/AIDS and kidney transplant patients.

"Immune suppression is really the only thing they share," he told AFP.

"What we found is that the extent of cancer occurrences in these two populations was very similar. Both had increased rates in a wide variety of cancers."

The research analysed the results of 12 previous studies completed in Australia, the US, Europe and Canada and involving more than 444,000 people with HIV/AIDS and some 32,000 organ recipients.

It found that of the 28 cancers studied, both groups were at a significant risk of developing 20 of them including cancer of the liver, stomach, cervix, eye, lip, mouth and penis.

HIV/AIDS patients were found to be 11 times more likely to develop Hodgkin's lymphoma while those who had undergone a transplant were almost four times more likely to develop the disease.

Grulich said most of the 20 cancers were mostly linked to infection.

He said for those cancers not linked to viruses or bacteria, such as breast and prostate cancer, both groups had similar rates to the general population.

"Until now, the accepted wisdom was that there were only three cancers associated with HIV - this paper finds that it is more like 20," he said.

Grulich, who works at the university's National Centre in HIV Epidemiology and Clinical Research, said the findings could overturn the previously held view that some of these cancers were linked to lifestyle risks such as smoking and sexual practices rather than infection.

"We believe that the finding points to an immune deficiency and not those other riskfactors," he said.

The results could change way HIV/AIDS patients are treated, he added.

"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 research comes ahead of a major international conference on HIV/AIDS which will take place in Sydney on J uly 22-24.