A recent study on the people carrying the human immunodeficiency virus has shown it to be linked with increased risk of cancer development in the humans. The reason for this might be a less efficient immune system in the HIV infected person.

"The study was done because we all know that now people with HIV are living longer and HIV is looking more like a chronic disease. So we wanted to look at one of the other very large chronic killers in America, cancer," said Dr. Pragna Patel of the U.S. Centers for Disease Control and Prevention, who was the lead author of the study.

The study focused on 54,780 men and women infected with the human immunodeficiency virus and saw the trends of cancer development in a period from 1992 to 2003.

The study found that cancers like Kaposi's sarcoma and non-Hodgkin lymphoma that have long been associated with people infected by the AIDS virus became relatively less common among HIV-infected people in the United States.

However, other type cancers like anal cancer, liver cancer and lung cancer are on the rise among these patients.

According to the study, during this period anal cancer became 59 times more common among HIV-infected people than the general population.

Hodgkin's disease was 18 times more common, liver cancer 7 times more common, lung cancer 3.6 times more common, the skin cancer melanoma and throat cancer both three times more common, and colorectal cancer 2.4 times more common.

The study also found that HIV-infected people had a reduced risk for prostate cancer. The researchers believe that this might be due to low levels of testosterone in the HIV infected men. This could be protective against prostate cancer.

"Most significant was the finding of anal cancer being so elevated even in the HAART era," Patel said.

In the 1990s, a drug therapy called highly active antiretroviral therapy, or HAART,was developed which helped greatly in extending the lives of many HIV-infected people.

The researchers believe that the increased risk may be linked to the anal sex by homosexual men. This can lead to the spread the human papillomavirus, or HPV, which is known to cause anal cancer.

Human papillomaviruses are common viruses which can cause various cancers and are transferred through sexual contact with an infected partner.

"Of course, anal sex and how many times you have anal sex and how many sex partners you have, that all matters with regard to HPV infection," Patel said.