[Detection of malondialdehyde-DNA adduct level by 32P-postlabeling assay in normal human esophageal epithelium and esophageal squamous cell carcinoma].
OBJECTIVE
To study whether the main malondialdehyde-DNA adduct (M1-dG) produced by lipid peroxidation is involved in the carcinogenesis of esophagus.


METHODS
DNA samples were isolated from normal esophageal epithelium (n = 32) obtained by biopsy and esophageal squamous cell carcinoma specimens (n = 30) obtained by surgery. All tissue samples came from individuals living in Linxian, Henan, a high-risk area of esophageal cancer. Contents of M1-dG adducts were detected by 32P-postlabeling method.


RESULTS
M1-dG adducts were detectable both in the normal and cancerous tissue samples. However, normal esophageal epithelial tissues exhibited significantly lower levels of M1-dG adducts (median 3.4, range 1.7/10(8)-55.4/10(8) nucleotides) than those found in esophageal cancer tissues (median 14.1, range 1.4/10(8)-59.0/10(8) nucleotides, P < 0.0001). The adduct levels were neither associated with gender, age, tobacco smoking status or genetic polymorphism in the CYP2E1, an enzyme participating in the oxidation of ethanol to form reactive free radicals.


CONCLUSIONS
Our findings provide evidence that DNA damage, resulted from lipid peroxidation, can accumulate in the normal human esophageal tissue and reach relatively high level in cancer tissue which suggests that M1-dG adducts may be involved in the initiation and progression of cancer with its mutagenic and carcinogenic effects.
Xing
D
D
Cancer Institute (Hospital), Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
Song
N
N
Tan
W
W
D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D019392:Cytochrome P-450 CYP2E1; D018736:DNA Adducts; D004273:DNA, Neoplasm / Q000032:analysis*; D004848:Epithelium; D004938:Esophageal Neoplasms / Q000235:genetics*; D004947:Esophagus; D006801:Humans; D007553:Isotope Labeling; D008315:Malondialdehyde; D010761:Phosphorus Radioisotopes
D018736:DNA Adducts; D004273:DNA, Neoplasm; D010761:Phosphorus Radioisotopes; D008315:Malondialdehyde; D019392:Cytochrome P-450 CYP2E1