Concentrations of the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether (2,2',4,4'-TeBDE) in the adipose tissue of 77 individuals from Sweden were determined. The subjects were recruited during the time period 1995-97 and encompassed both men and women ranging from 28 to 85 years in age. Of the subjects included, 19 patients had non-Hodgkin's lymphoma (NHL), 23 patients had malignant melanoma, 8 patients had other cancers or in situ changes, and 27 persons had no cancer diagnosis. The mean concentration of 2,2',4,4'-TeBDE was 5.1 ng/g lipid (range 0.6-27.5) for the 27 persons without malignancies. For NHL patients the mean concentration was 13.0 ng/g lipid (range 1.0-98.2). A nonsignificantly elevated risk with dose response was found for NHL when the cases and controls were compared in the two highest concentration groups (2.05-< 5.43 ng/g lipid and > or = 5.43 ng/g lipid) with the lowest group (< 2.05 ng/g lipid) yielding odds ratio (OR) 1.9 with 95% confidence interval (CI) 0.3-14 and OR 3.8, CI 0.7-26, respectively. The results for the patients with malignant melanoma did not differ from the controls.