Possible association of beta(2)- and beta(3)-adrenergic receptor gene polymorphisms with susceptibility to breast cancer

Background: The involvement of beta (2)-adrenergic receptor (ADRB2) and bet a (3)-adrenergic receptor (ADRB3) in both adipocyte lipolysis and thermogen ic activity suggests that polymorphisms in the encoding genes might be link ed with interindividual variation in obesity, an important risk factor for postmenopausal breast cancer. In order to examine the hypothesis that genet ic variations in ADRB2 and ADRB3 represent interindividual susceptibility f actors for obesity and breast cancer, we conducted a hospital-based, case-c ontrol study in the Aichi Cancer Center, Japan. Methods: A self-administered questionnaire was given to 200 breast cancer p atients and 182 control individuals, and pertinent information on lifestyle , family history and reproduction was collected. ADRB2 and ADRB3 genotypes were determined by polymerase chain reaction (PCR) restriction fragment len gth polymorphism assessment. Results: Twenty-five (12.4%) breast cancer patients and 32 (17.6%) control individuals were found to bear a glutamic acid (Glu) allele for the ADRB2 g ene (odds ratio [OR] 0.67, 95% confidence interval [CI] 0.38-1.18), and 60 (30.0%) breast cancer patients and 61 (33.5%) control individuals were foun d to bear an Arg allele for the ADRB3 gene (OR 0.85, 95% CI 0.55-1.31). A s ignificantly lower risk was observed in those who carried the Glu ADRB2 all ele and who reported first childbirth when they were younger than 25 years (OR 0.35, 95% CI 0.13-0.99). Conclusion: A potential association may exist between risk of breast cancer and polymorphisms in the ADRB2 and ADRB3 genes; further studies in larger samples and/or in different ethnic groups are warranted to investigate this potential association.