S. Lagorio et al., EXPOSURE TO BENZENE AND URINARY CONCENTRATIONS OF 8-HYDROXYDEOXYGUANOSINE, A BIOLOGICAL MARKER OF OXIDATIVE DAMAGE TO DNA, Occupational and environmental medicine, 51(11), 1994, pp. 739-743
Objectives-Benzene is an established animal and human carcinogen. The
mechanism of benzene toxicity, particularly its leukaemogenic effect,
is not fully understood. The modified base 8-hydroxy-deoxyguanosine (8
-OHdG) is a sensitive marker of the DNA damage due to hydroxyl radical
attack at the C8 of guanine. This damage, if left unrepaired, has bee
n proposed to contribute to mutagenicity and cancer promotion. We cond
ucted this biomonitoring study with the aim of evaluating the associat
ion between excretion of 8-OHdG and level of exposure to benzene and o
ther aromatic compounds among occupationally exposed people. Methods-A
random sample of 65 filling station attendants from Rome, Italy was s
tudied for personal exposure to benzene, toluene, and xylenes, and exc
retion of 8-OHdG. Information about age, length of employment, smoking
habits, and diagnostic exposure to x rays was collected by questionna
ire. An average yearly level of exposure to benzene and methylbenzenes
was calculated for each filling station attendant on the basis of abo
ut seven repeated personal samples collected during one year. A spot s
ample of 20 ml of urine was collected from each worker. Concentrations
of 8-OHdG were determined by high performance liquid chromatography (
HPLC) with coupled columns. Results-A mean (SD) concentration of 1.36
(0.49) pmol of 8-OHdG/mol of creatinine was measured. A significant co
rrelation was found between urinary 8-OHdG and exposure to benzene (r
0.34). In a multiple regression analysis relating the concentration of
urinary 8-OHdG with the age, length of employment, smoking, diagnosti
c exposure to x rays and personal exposure to benzene, an increase of
0.15 mu mol/mol creatinine in urinary 8-OHdG/unit increase in the natu
ral logarithm of the average yearly benzene concentration was estimate
d. Conclusion-This study shows a dose-response effect between personal
exposure to benzene and urinary 8-OHdG concentration; further studies
are needed to clarify the biological significance of 8-OHdG as a mark
er of cancer risk.