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Filter by:Burkitt lymphoma (BL) is an aggressive monoclonal B-cell malignancy that is rare (sporadic) worldwide, but is 100-fold more common (endemic) in equatorial Africa, particularly among children. Epstein-Barr virus (EBV) and malaria are epidemiologically linked to endemic BL in epidemiologic studies, but questions remain about role of EBV variants and the evidence for association with malaria is weak. EBV is ubiquitous, yet only few children develop BL, possibly because only a few EBV variants are pathogenically relevant. The association of BL with malaria is based on ecologic and non-comparative clinical studies. Two case-control studies have reported significant association of high anti-malarial antibodies with BL (OR=5_ among children in Uganda and in Malawi, but selection bias (cases and controls came from dissimilar geographical areas) and reverse causality bias were limitations. Three studies were conducted in the 1960s and 70s to test association of carriage of malaria-resistance gene with BL, two of which reported a significant or marginal inverse association. These pioneering studies were small (240 cases all together) and looked at one polymorphism in one gene (sickle cell gene). Improvements in technologies to characterize genetic variation allow the EBV and malaria hypotheses to be examined with greater power by looking at genetic variation across multiple genes. Epidemiology of Burkitt lymphoma in East African children and minors (EMBLEM) is a case-control study of 1500 BL cases and 3000 age-, sex- and residence-frequency matched controls we are proposing to conduct in East Africa. The study will enroll cases at four hospitals in four regions in East Africa, where malaria transmission is holoendemic and year round. The controls will be enrolled from general population attendees at Health Center II (HC-II) units where the cases originated. The primary study objectives are: 1) to test the hypothesis that genetic resistance to malaria is associated with a lower risk of BL, and 2) to use genome-wide association methods to discover genetic variation that may be associated with decreased or increased risk of BL. Because genetic variation conveys no information on actual exposure to malaria or EBV, in secondary analyses, we will use empiric epidemiological questionnaire and laboratory methods: a) to measure exposure to malaria and its association with BL, and b) to measure EBV variants and their association with BL. To examine issues related to bias and to obtain data to correct for deviations, we will also enroll 2250 population controls from 5% of the villages to obtain population distribution of key exposures variables. This data will be used to reweight the distribution in HC-II controls back to the general population. ...
Nasopharyngeal carcinoma is a rare tumor among Caucasians which occurs with high incidence among individuals of Chinese descent. The disease is believed to have a multifactorial etiology with genetic, viral, and other environmental factors being involved. Little is known, however, about the genetic component of this disease. We have recently completed subject recruitment for a case-control study of NPC in Taiwan. Using information obtained from the NPC cases recruited into this NCI-sponsored case-control study as well as from a parallel cross-sectional study conducted by our Taiwanese collaborators, we have been able to identify 120-150 families with multiple family members affected with NPC. The purpose of the study described herein is to determine the role of inherited genetic factors in the etiology of NPC and to examine the effect of these genetic susceptibility factors on risk associated with environmental exposures. Families will initially be contacted via the proband who previously participated in our case-control and cross-sectional studies. Subsequently, informative family members will be asked to visit the study clinic to participate in the study. A family history questionnaire will be administered to the proband from each of the families selected for study. In addition, a risk factor questionnaire will be administered to all participating family members, and 30-40 ml of blood and an oral sample will be obtained from each study participant. Additional study components include medical record review to verify the diagnosis of NPC, retrieval of tumor tissue blocks as a source of DNA for study, and clinical exams on a sample of unaffected individuals to exclude the possibility of prevalent, undetected disease among family members. Oral and laryngeal cancer families will also be recruited in a manner similar to that described for NPC families, in an attempt to elucidate genetic factors linked to the development of these two cancers....