Benzene Exposure and Risk of Non-Hodgkin Lymphoma

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Published online first on March 2, 2007

[Cancer Epidemiology Biomarkers & Prevention, 10.1158/1055-9965.EPI-06-1057]

Benzene Exposure and Risk of Non-Hodgkin Lymphoma

Martyn T. 1*, M. , Allan H.

1 Center for Occupational and Environmental Health, School of Public Health,

University of California, Berkeley, California

* To whom correspondence should be addressed. E-mail: martynts@... .

Abstract

Exposure to benzene, an important industrial chemical and component of gasoline,

is a widely recognized cause of leukemia, but its association with non-Hodgkin

lymphoma (NHL) is less clear. To clarify this issue, we undertook a systematic

review of all case-control and cohort studies that identified probable

occupational exposures to benzene and NHL morbidity or mortality. We identified

43 case-control studies of NHL outcomes that recognized persons with probable

occupational exposure to benzene. Forty of these 43 (93%) studies show some

elevation of NHL risk, with 23 of 43 (53%) studies finding statistically

significant associations between NHL risk and probable benzene exposure. We also

identified 26 studies of petroleum refinery workers reporting morbidity or

mortality for lymphomas and all neoplasms and found that in 23 (88%), the rate

of lymphoma morbidity or mortality was higher than that for all neoplasms. A

substantial healthy-worker effect was evident in many of the studies and a

comprehensive reevaluation of these studies with appropriate adjustments should

be undertaken. Numerous studies have also reported associations between benzene

exposure and the induction of lymphomas in mice. Further, because benzene is

similar to alkylating drugs and radiation in producing leukemia, it is plausible

that it might also produce lymphoma as they do and by similar mechanisms.

Potential mechanisms include immunotoxicity and the induction of double-strand

breaks with subsequent chromosome damage resulting in translocations and

deletions. We conclude that, overall, the evidence supports an association

between occupational benzene exposure and NHL. (Cancer Epidemiol Biomarkers Prev

2007;16(3):385-91)

Key Words: Solvents, NHL, Refinery, Epidemiology, Hematology