TY - JOUR
T1 - Quantitative comparison of aflatoxin B1 serum albumin adducts in humans by isotope dilution mass spectrometry and ELISA
AU - Scholl, Peter F.
AU - Turner, Paul C.
AU - Sutcliffe, Anne E.
AU - Sylla, Abdoulaye
AU - Diallo, Momadou S.
AU - Friesen, Marlin
AU - Groopman, John D.
AU - Wild, Christopher P.
PY - 2006/4
Y1 - 2006/4
N2 - Metabolic activation of the hepatocarcinogenic mycotoxin aflatoxin B1 (AFB1) results in the covalent attachment of AFB1 to serum albumin. Digestion of adducted albumin releases AFB1-lysine, a biomarker of exposure status. AF-albumin adducts have been most frequently measured in precipitated serum albumin using an immunoassay (ELISA); however, a sensitive and specific isotope dilution mass spectrometric (IDMS) assay for measurement of AFB1-lysine in serum has recently been developed. The ELISA and IDMS methods were compared using 20 human sera collected in Guinea, West Africa, where AF exposure is endemic. Measurement of AFB1-lysine adduct concentrations by IDMS in serum and albumin precipitated from the same sample revealed that precipitation has no effect on the measured adduct levels. The concentration of AF-albumin adducts measured by ELISA and AFB1-lysine measured by IDMS in 2 mg of albumin were well correlated (R = 0.88, P < 0.0001); however, AF-albumin adduct concentrations measured by ELISA were on average 2.6-fold greater than those of the AFB1-lysine adduct. Although these data suggest that the ELISA is measuring other AF adducts in addition to AFB1-lysine, these biomarkers are comparable in their ability to assess AF exposure at AF-albumin concentrations ≥3 pg AFB1-lysine equivalents/mg albumin. Identification of other adducts may clarify the mechanistic basis for using AF-protein biomarkers to assess exposure status in future epidemiologic studies of liver cancer.
AB - Metabolic activation of the hepatocarcinogenic mycotoxin aflatoxin B1 (AFB1) results in the covalent attachment of AFB1 to serum albumin. Digestion of adducted albumin releases AFB1-lysine, a biomarker of exposure status. AF-albumin adducts have been most frequently measured in precipitated serum albumin using an immunoassay (ELISA); however, a sensitive and specific isotope dilution mass spectrometric (IDMS) assay for measurement of AFB1-lysine in serum has recently been developed. The ELISA and IDMS methods were compared using 20 human sera collected in Guinea, West Africa, where AF exposure is endemic. Measurement of AFB1-lysine adduct concentrations by IDMS in serum and albumin precipitated from the same sample revealed that precipitation has no effect on the measured adduct levels. The concentration of AF-albumin adducts measured by ELISA and AFB1-lysine measured by IDMS in 2 mg of albumin were well correlated (R = 0.88, P < 0.0001); however, AF-albumin adduct concentrations measured by ELISA were on average 2.6-fold greater than those of the AFB1-lysine adduct. Although these data suggest that the ELISA is measuring other AF adducts in addition to AFB1-lysine, these biomarkers are comparable in their ability to assess AF exposure at AF-albumin concentrations ≥3 pg AFB1-lysine equivalents/mg albumin. Identification of other adducts may clarify the mechanistic basis for using AF-protein biomarkers to assess exposure status in future epidemiologic studies of liver cancer.
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U2 - 10.1158/1055-9965.EPI-05-0890
DO - 10.1158/1055-9965.EPI-05-0890
M3 - Article
C2 - 16614131
AN - SCOPUS:33646267699
SN - 1055-9965
VL - 15
SP - 823
EP - 826
JO - Cancer Epidemiology Biomarkers and Prevention
JF - Cancer Epidemiology Biomarkers and Prevention
IS - 4
ER -