Akio Hara1,2, Naruto Taira3,4, Taeko Mizoo1,2, Keiko Nishiyama1,2, Tomohiro Nogami1,2, Takayuki Iwamoto2, Takayuki Motoki2, Tadahiko Shien1,2, Junji Matsuoka2, Hiroyoshi Doihara1,2, Setsuko Ishihara5, Hiroshi Kawai6, Kensuke Kawasaki7, Youichi Ishibe8, Yutaka Ogasawara7, Shinichiro Miyoshi1. 1. Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-city, Okayama, 700-8558, Japan. 2. Department of Breast and Endocrinological Surgery, Okayama University Hospital, Okayama, Japan. 3. Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-city, Okayama, 700-8558, Japan. ntaira@md.okayama-u.ac.jp. 4. Department of Breast and Endocrinological Surgery, Okayama University Hospital, Okayama, Japan. ntaira@md.okayama-u.ac.jp. 5. Department of Radiology, Okayama Saiseikai General Hospital, Okayama, Japan. 6. Department of Breast Surgery, Okayama Rousai Hospital, Okayama, Japan. 7. Department of Breast and Endocrinological Surgery, Kagawa Prefectural Central Hospital, Takamatsu, Japan. 8. Department of Breast Surgery, Mizushima Kyodo Hospital, Okayama, Japan.
Abstract
BACKGROUND: Recent studies have suggested that the association between smoking and breast cancer risk might be modified by polymorphisms in the N-acetyltransferase 2 gene (NAT2). Most of these studies were conducted in Western countries, with few reports from East Asia. METHODS: We conducted a case-control study of 511 breast cancer cases and 527 unmatched healthy controls from December 2010 to November 2011 in Japan. Unconditional logistic regression was used to analyze the association of smoking with breast cancer risk stratified by NAT2 phenotype. RESULTS: In this population, 11 % of the cases and 10 % of the controls were classified as a slow acetylator phenotype. Compared to never smokers, current smokers had an increased breast cancer risk in multivariate analysis [odds ratio (OR) = 2.27, 95 % confidence interval (95 %CI) = 1.38-3.82]. Subgroup analyses of menopausal status indicated the same tendency. Subgroup analyses of NAT2 phenotype, the ORs in both of rapid and slow acetylator phenotype subgroups were comparable, and no interactions were observed between smoking status and NAT2 phenotype (p = 0.97). A dose-dependent effect of smoking on breast cancer risk was seen for the rapid acetylator phenotype, but not for the slow acetylator phenotype. CONCLUSION: Given the high frequency of the rapid acetylator phenotype, these results show that smoking is a risk factor for breast cancer among most Japanese women. It may be of little significance to identify the NAT2 phenotype in the Japanese population.
BACKGROUND: Recent studies have suggested that the association between smoking and breast cancer risk might be modified by polymorphisms in the N-acetyltransferase 2 gene (NAT2). Most of these studies were conducted in Western countries, with few reports from East Asia. METHODS: We conducted a case-control study of 511 breast cancer cases and 527 unmatched healthy controls from December 2010 to November 2011 in Japan. Unconditional logistic regression was used to analyze the association of smoking with breast cancer risk stratified by NAT2 phenotype. RESULTS: In this population, 11 % of the cases and 10 % of the controls were classified as a slow acetylator phenotype. Compared to never smokers, current smokers had an increased breast cancer risk in multivariate analysis [odds ratio (OR) = 2.27, 95 % confidence interval (95 %CI) = 1.38-3.82]. Subgroup analyses of menopausal status indicated the same tendency. Subgroup analyses of NAT2 phenotype, the ORs in both of rapid and slow acetylator phenotype subgroups were comparable, and no interactions were observed between smoking status and NAT2 phenotype (p = 0.97). A dose-dependent effect of smoking on breast cancer risk was seen for the rapid acetylator phenotype, but not for the slow acetylator phenotype. CONCLUSION: Given the high frequency of the rapid acetylator phenotype, these results show that smoking is a risk factor for breast cancer among most Japanese women. It may be of little significance to identify the NAT2 phenotype in the Japanese population.
Entities:
Keywords:
Breast cancer; Japanese; NAT2; Single nucleotide polymorphism; Smoking