Serum albumin adducts in the molecular epidemiology of aflatoxin carcinogenesis: correlation with aflatoxin B1 intake and urinary excretion of aflatoxin M1

Abstract

Aflatoxin-serum albumin adducts in the blood of 42 residents of Guangxi Province, People's Republic of China, were determined and compared with intake of aflatoxin B ₁ (AFB ₁ ) and excretion of aflatoxin M ₁ (AFM ₁ ) in urine. Blood specimens were obtained during the same period that urine was collected and that diet was sampled. Serum albumin was isolated from blood by affinity chromatography on Reactive Blue 2-Sepharose and subjected to enzymatic proteolysis using Pronase. Immunoreactive products were purified by immunoaffinity chromatography and quantified by competitive radioimmunoassay. A highly significant correlation (r = 0.60, P < 0.00003) of adduct level with AFM, excretion was observed. An equally highly significant correlation of adduct level with intake (r = 0.69, P < 0.000001) was also observed. From the slope of the regression line for adduct level as a function of intake, it was calculated that 1.4–2.3% of ingested AFB ₁ becomes covalently bound to serum albumin, a value very similar to that observed when rats are administered AFB ₁ .