Risk Factors for Non-HIV-Related Kaposi s Sarcoma

Overview

This study will try to identify risk factors for Kaposi s sarcoma, a rare skin cancer, and to understand the role of the KSHV virus in development of the disease. All native-born Italians 21 years of age or older residing in Sicily from July 1, 2002 through June 30, 2005 who have Kaposi s sarcoma not related to HIV infection may be eligible for this study. Healthy control subjects will also be enrolled. All participants will be interviewed about their childhood, jobs, habits, medical conditions, and treatments. They also will provide a blood sample and a saliva sample, obtained by swishing a mouthwash for 45 seconds and spitting it into a container. Blood will be tested for two viruses KSHV and HIV that are related to Kapsosi s sarcoma. The KSHV virus is newly discovered and not well understood. In general, a positive KSHV test probably means an infection with the virus has occurred in the past, but not necessarily that disease has developed. HIV is the virus that causes AIDS. People with AIDS have a high risk of Kapsosi s sarcoma. Although HIV and AIDS are very rare among older adults in Sicily, the presence of HIV must be ruled out in order to understand how KSHV is related to Kapsosi s sarcoma. The blood may also be used to measure immunity (the body s defense against infection and cancer) and for genetic studies to help discover why Kapsosi s sarcoma occurs.

Persons infected with the Kaposi s sarcoma-associated herpesvirus (KSHV) are at risk for developing Kaposi s sarcoma (KS), but the risk factors for KSHV infection and for KS following infection are not well defined. Classical KS (cKS) occurs without apparent immune deficiency (such as AIDS or an allograft). The proposed study will test specific hypotheses and generate new hypotheses on the risk of cKS among persons who have antibodies against KSHV, on the risk of KSHV seropositivity, and on the risk of active KSHV infection, defined as KSHV viremia or viral shedding in saliva. To do so, 120 incident cases of cKS from throughout Sicily and approximately 1800 persons (15% KSHV seropositive) of similar age, sex, and community size will be asked to participate by providing questionnaire data and blood and saliva specimens. Residual formalin-fixed, paraffin embedded tissue from KS skin biopsies will be available for verification of diagnosis and molecular analyses. Primary hypotheses are focused on host genetic susceptibility, endogenous clinical conditions (such as asthma and allergy), and exogenous exposures (cigarette smoking and contact with certain plants, water and soil) that are postulated to affect KSHV activation, dissemination, and disease induction. The study will have sufficient statistical power to detect factors that increase the risk of KSHV seropositivity by 1.5- to 2-fold, the risk of cKS by 2- to 3-fold, and the risk of KSHV viremia or shedding by 3- to 4-fold.