A functional C-G polymorphism in the CYP7B1 promoter region and its different distribution in Orientals and Caucasians.
Cytochrome P450 (CYP) 7B1 is involved in many metabolic processes including androgen metabolism. Genetic variation in the CYP7B1 gene may play a role in predisposition to prostate cancer. Here, we screened the human CYP7B1 gene for possible polymorphisms. Only one single polymorphism was detected, a C-G change in the promoter -104 base pair from the transcription start site. The allele frequency was investigated in Swedish men and compared to a Korean population, as it is known that the frequency of prostate cancer is low among Orientals. We found that the frequency of the G-allele was 4.04% in Swedes (n=150) but only 0.33% among Koreans (n=153). Computer analysis indicated that the two variants bind with different affinities to a CCAAT-box binding protein. Expression studies with reporter constructs showed significantly higher transcriptional activity of the G variant in Hek293 cells (2.7-fold, P<0.05). In conclusion, we report here for the first time the detection of a single polymorphism in the CYP7B1 gene. This polymorphism is associated with phenotypic differences in an expression system and a widely different allele frequency in two ethnic populations, with great differences in the incidence of prostate cancer.
Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden. jenny.jakobsson@labmed.ki.se
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J
Jakobsson
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H
Karypidis
J-E
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Johansson
H-K
HK
Roh
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A
Rane
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Ekström
D044466:Asian People / Q000235:genetics*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D000072474:Cytochrome P450 Family 7; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011471:Prostatic Neoplasms / Q000235:genetics; D013250:Steroid Hydroxylases / Q000235:genetics*; D044465:White People / Q000235:genetics*
D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; C115867:oxysterol 7-alpha-hydroxylase; D000072474:Cytochrome P450 Family 7; C499571:CYP7B1 protein, human