Association of polymorphisms and haplotypes in the cytochrome P450 1B1 gene with uterine leiomyoma: A case control study.

Uterine leiomyoma (UL) is an estrogen-dependent neoplasm of the uterus and estrogen metabolizing enzymes affect its promotion and progression. The aim of the present study was to evaluate the association between four single-nucleotide polymorphisms (SNPs) of the cytochrome P450 1B1 (CYP1B1) gene and UL risk. Four SNPs of the CYP1B1 gene in 105 UL patients and 112 unrelated healthy controls were genotyped using a direct sequencing method. Haplotype analyses were performed with UNPHASED software and linkage disequilibrium (LD) was assessed by Haploview software. There were no associations between Leu432Val (rs1056836), Asp449Asp (rs1056837) and Asn453Ser (rs1800440) polymorphisms of the CYP1B1 gene and UL. Although the genotypic frequencies of the Arg368His (rs79204362) polymorphism did not differ between the two groups, the frequency of A (His) allele was significantly higher in UL females (P=0.02). In addition, the frequency of GTAA haplotype was significantly higher in the controls and played a protective role in UL susceptibility. A strong LD between the three common SNPs (rs1056836, rs1056837 and rs1800440) in the CYP1B1 gene was observed in the population. In conclusion, a higher frequency of the CYP1B1 368His (A) allele was observed in UL females. The frequency of the GTAA haplotype was significantly higher in healthy females and this haplotype played a protective role in UL susceptibility.