[Association of nasopharyngeal carcinoma risk with cytochrome P450 CYP1A1 gene polymorphisms].
OBJECTIVE
To investigate the association between CYP1A1 gene polymorphisms and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families through family-based association study.


METHODS
A total of 457 Cantonese nuclear families,consisting of 2134 members, were recruited as subjects. Each family included two parents and at least one offspring with nasopharyngeal carcinoma. Two single nucleotide polymorphisms (SNP) in CYP1A1 named m1 (rs4646903) and m2 (rs1048943), were genotyped by PCR-RFLP assay and verified by directly sequencing. The genotype data were analyzed with family-based association test (FBAT) software to check the linkage and association between the two genetic markers and susceptibility of nasopharyngeal carcinoma.


RESULTS
FBAT analysis showed that the minor allele frequencies (MAF) of the two SNP were 0.442 (C) and 0.339 (G) respectively. For m1 polymorphism in CYP1A1 gene was not significantly associated with nasopharyngeal carcinoma in our study population whether stratified with VCA-IgA or not (without stratification: chi2 = 2.399, P = 0.301; with stratification: low-titer group (VCA-IgA <1:80), MAF = 0.457 (C), chi2 = 1.221, P = 0.543; high-titer group (VCA-IgA > or = 1:80), MAF = 0.427 (C), chi2 =2.832, P = 0.243) . For m2 polymorphism, when VCA-IgA <1:80, the G allele showed decreased transmission under additive and dominant model (MAF = 0.347 (G); Zadditive = -2.120, Padditive = 0.034; Zdominant = - 2.303, Pdominant = 0.021) and a boundary P value was got with global statistic (chi2 = 5.394, P = 0.067) . Haplotype TG (0.057), constructed by m1 and m2, might decrease nasopharyngeal carcinoma risk (Z= -2.002, P=0.045). A boundary P value was also got with global statistic (chi2 =7.067, P=0.070).


CONCLUSIONS
There was no statistical significance between m1 polymorphism and susceptibility of nasopharyngeal carcinoma in Cantonese nuclear families. And this study showed that m2 polymorphism might associated with the decrease of nasopharyngeal carcinoma in Cantonese nuclear families.
Xu
Ya-Fei
YF
Department of Experimental Research, Cancer Center, Sun Yat-sen University, Guangzhou, China.
Pan
Qing-Hua
QH
Cui
Cui
C
Chen
Li-Zhen
LZ
Feng
Qi-Sheng
QS
Zeng
Yi-Xin
YX
Jia
Wei-Hua
WH
D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
D019363:Cytochrome P-450 CYP1A1