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The expression level of human telomerase reverse transcriptase (hTERT), a catalytic subunit of telomerase, is a major determinant of telomerase activity, and may have a key role in regulating telomere length and affect cancer susceptibility. We explored the associations between a functional variant of hTERT MNS16A and breast cancer risk among 278 sister-sets (296 cases and 353 controls). Variant of hTERT MNS16A was genotyped by a PCR method and classified as carrying short (S: 243 or 272bp) or long (L: 302 or 333bp) alleles according to previous functional studies. Totally, nine genotypes were obtained among the sisters (243/243, 272/243, 302/243, 302/272, 333/243, 333/272, 302/302, 333/302 and 333/333), and three of them were commonly observed (243/243, 302/243 and 302/302). No significant increase in overall breast cancer risk was observed for carriers of hTERT homozygous S allele (OR = 1.46, 95%CI: 0.75-2.84) compared with carriers of L allele (P = 0.26). No case-control differences of hTERT MNS16A genotyping by DNA repair capacity (DRC) status, benign breast disease history, ever use hormonal contraceptives, ever smoking and ever alcohol drink history were observed. These data indicate that variant of hTERT MNS16A may not modulate breast cancer susceptibility.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA