Letter From the Editor
Cancer has been associated with AIDS before the human immunodeficiency virus was even identified. The telltale purple-brown lesions of Kaposi's sarcoma (KS) were one of the characteristic signs of an epidemic coming into its own. In the very early days of AIDS, many patients with nowhere to turn were being referred to cancer centers for care only to find out that (as with the rest of the general medical community) there was great fear, and many clinicians were reluctant to go anywhere near them. As an understanding of HIV and AIDS grew, so did the realization that a weakened immune system allowed opportunistic infections to take over, eventually leading to death.
But why cancer? Until AIDS came on the scene, KS was a relatively rare cancer that was endemic in certain populations, such as older men of Mediterranean descent. Indeed, a great deal of interest was generated in finding out why this particular cancer was associated with AIDS in many patients. In the mid-1990s, the discovery of Kaposi's sarcoma-associated herpesvirus (or human herpesvirus 8) in patients with AIDS provided an answer. That virus, normally suppressed by a healthy immune system, can be sexually transmitted and can cause cancer under biological conditions of immunosuppression. This scenario is similar to what happens with invasive cervical cancer, another AIDS-defining cancer, with the viral agent being human papillomavirus. (Of course, cervical cancer is a risk for all women, but even more so for women with HIV infection.) Another example is non-Hodgkin's lymphoma, which is associated with Epstein-Barr virus (the virus that causes mononucleosis or the "kissing disease"). In fact, all AIDS-defining cancers are caused by or strongly associated with viruses.
The connection between viruses, the immune system, and cancer has been better explored and defined since the discovery of HIV. But improved understanding of immunity and virology has led to even more questions. In addition, antiretroviral therapy has changed the landscape of HIV and cancer: severe immunosuppression is not necessarily the only key factor that allows AIDS-defining cancers to emerge. The risks of cancer transcend whether or not a patient has a certain number of CD4 T cells. People living with HIV are surviving on treatment, but getting a wider variety of cancers at different rates than in the uninfected population. Lung, testicular, and anal cancers are some of the new malignancies being seen in the HIV-infected population with growing frequency. Is this a product of survival with incomplete immune restoration? If so, what can be done to improve therapy for HIV? In the meantime, how are such cancers best treated in the context of HIV? Only time and fervent research will provide answers.
This issue of RITA! explores the latest epidemiological data on HIV/AIDS and cancer, the mechanisms of pathogenesis behind some of these malignancies, current philosophies of treatment, and available resources for research. But there are growing challenges in this important area of HIV research and treatment. In the current economy, with spending cuts in research as well as in public dollars to fund medications and treatment for those in need, a crisis is looming. Because immune dysfunction is a common thread between HIV and cancer, research on HIV-associated malignancies must remain a priority.
Cancer is a devastating disease that has plagued humankind for far longer than HIV/AIDS. Yet, where these diseases overlap has remained a fruitful field of endeavor for basic science and clinical research. May cures be found on the fronts of both diseases in the years to come.
Very truly yours,
Thomas Gegeny, M.S., E.L.S.
This article was provided by The Center for AIDS. It is a part of the publication Research Initiative/Treatment Action!. Visit CFA's website to find out more about their activities and publications.