title: B-cell non-Hodgkin's lymphoma and hepatitis C virus infection: a systematic review.
abstract: A high prevalence of hepatitis C virus (HCV) infection in patients with B-cell non-Hodgkin's lymphoma (B-NHL) has been reported in some, but not all, studies, and the association showed a strong regional variation. We conducted a systematic review of the prevalence of HCV infection in case series of B-NHL and, when an appropriate control group was available, of the odds ratio of B-NHL associated with HCV infection. A high HCV prevalence in B-NHL was found in southern and eastern Europe, Japan and the southern United States, but not in central and northern Europe, Canada, northern United States, or a few Asian countries. Possible sources of heterogeneity and bias are discussed. The odds ratio of B-NHL for HCV infection was relatively weak, ranging from 2 to 4 in most studies. Thus, even if the observed association were causal, the percentage of cases of B-NHL attributable to HCV infection would be relatively low (10%) also in countries with a high prevalence of HCV infection in the general population, and extremely low in other countries. This may explain apparent inconsistencies between studies. Potential mechanisms of action are also discussed.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. evanegri@marionegri.it
authors.forename: Eva
authors.initials: E
authors.lastname: Negri
authors.forename: D'Anna
authors.initials: D
authors.lastname: Little
authors.forename: Mauro
authors.initials: M
authors.lastname: Boiocchi
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.forename: Silvia
authors.initials: S
authors.lastname: Franceschi
mesh_terms: D016022:Case-Control Studies; D016021:Epidemiologic Studies; D005060:Europe / Q000453:epidemiology; D006526:Hepatitis C / Q000150:complications* / Q000453:epidemiology*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016393:Lymphoma, B-Cell / Q000209:etiology* / Q000821:virology*; D008228:Lymphoma, Non-Hodgkin / Q000209:etiology* / Q000821:virology*; D009656:North America / Q000453:epidemiology; D016017:Odds Ratio; D015995:Prevalence