Why People with HIV Have Higher Cancer Risk

New study revealed how the virus could affect cancer cells.

A new study shows how tiny intercellular bubbles may play a big role in altering the growth and spread of cancer in people who are HIV positive.

Researchers with the Case Western Reserve University’s School of Dental Medicine studied 18 HIV-positive people with head and neck cancer, and found that exosomes or nanocarriers that transfer DNA, RNA, and proteins to cells, also promote cancer cells.

As a result, this new research may show why cancer grows faster and more aggressively in patients with HIV, said Ge Jin, PhD, associate professor of biological sciences at the School of Dental Medicine and the study’s author and principal investigator.

“The cells in question release exosomes into the bloodstream — think small nanoparticles — that don’t cause cancer, but they support it,” Jin said. “There are big implications here.”

“They assist in a way we hadn’t — until now — been able to understand,” Jin added.

AIDS, HIV, and cancer risk

For many years, much of the focus in medicine and research was on people with AIDS who had cancers directly associated with the virus, such as lymphoma.

But the new findings, published in Nature Communications, suggest an explanation as to why patients with HIV have higher rates of different kinds of cancer that aren’t often associated with AIDS, researchers said. Skin, lung, and anal cancers are some examples.

In fact, HIV-positive people are not only at an increased risk, but more likely to die of lung cancer and cancer in the head and neck, researchers noted.

People living with HIV are about 500 times more likely to be diagnosed with Kaposi’s sarcoma, a cancer that causes lesions to grow in the skin, lymph nodes, internal organs, and mucous membranes, according to the Institute and other medical experts.

People with HIV are also 12 times more likely to be diagnosed with non-Hodgkin’s lymphoma.

Women living with HIV are 3 times more likely to be diagnosed with cervical cancer.

Antiretroviral therapy, introduced in the mid-1990s, controls HIV by denying the virus a chance to replicate itself in the body; it also reduces the incidence of certain cancers in HIV-positive people. But cancer rates are still much higher among people with HIV compared to the general population, researchers said.

One common theory is that many people with HIV do not know they have the virus.

Dr. John Zaia, a clinician and principal investigator of the Alpha Stem Cell Clinic at City of Hope, in Duarte, California, said the latest research casts a new, interesting light on exosomes and the way they may be acting even with antiviral medication.

He described exosomes as tiny bubbles that transfer DNA, RNA, and messages to other cells.

Scientists are starting to realize how important exosomes are and how they could play a role in treatment of cancer overall. In his research, Zaia is internationally known for his research in gene therapy treatments for people with HIV, and also for examining the potential of gene therapy for cancer and other diseases for the general population at the City of Hope. He said the latest study on exosomes and HIV and cancer provides more insight.

“When I read this paper, it illustrated something new, which is that even viral infections that are controlled can have an effect on a person,” Zaia said. “This paper just illustrates a surprising discovery that was made: Even a virus locked into a cell, that can’t get out because the patient is taking antivirals… the virus can still communicate.”

The latest research was funded by the National Institutes of Health with two five-year grants, totaling nearly $4 million. The research was done in collaboration between Case Western Reserve University’s School of Dental Medicine and the School of Medicine, Case Comprehensive Cancer Center and the Center for AIDS Research.

Other theories for increased cancer risk

There are many other theories as to why people who are HIV-positive are more likely to develop cancer, said Dr. Carlos del Rio, co-director of Emory University’s Center for AIDS Research.

One is that HIV weakens the immune system so that the body can’t fight viral infections that could cause cancer, according to the National Cancer Institute.

But with HIV, physicians also look at behavioral risks such as smoking and heavy alcohol use, he added.

“A lot of things we do with treating patients with their HIV is getting them to stop smoking,” del Rio said.

In his practice, del Rio has seen an increase of people who are HIV positive with cancer and added that the latest research on exosomes could lead to a better understanding of the way cells communicate.

“It’s really interesting because this is the first paper that looks at mechanisms,” he said. “It’s exciting science and I think we need more information.”

The bottom line

Researchers with the Case Western Reserve University’s School of Dental Medicine studied 18 HIV-positive people with head and neck cancer and found that exosomes or nanocarriers that transfer DNA, RNA, and proteins to cells, also promote cancer cells. These exosomes or nanocarriers may help cancer cells.

People living with HIV are at increased risk of developing and dying from a variety of cancers including lung cancer, cancer in the head and neck, and Kaposi’s sarcoma.