Effect of Genetic Polymorphisms and Long-Term Tobacco Exposure on the Risk of Breast Cancer
Abstract
:1. Introduction
2. Results
- 1.
- Seventy-six patients who had never smoked with histologically verified breast carcinoma, non-smoker group.
- 2.
- One hundred forty-one smoker patients with histologically verified breast carcinoma.
- 3.
- Eighty healthy smoker women, with negative family or personal history and with negative breast findings.
2.1. Smoking’s Impact on Clinical Variables and Breast Cancer
2.2. Analysis of Genetic Polymorphisms
2.3. Relationship between Smoking Habits, Clinical Variables and Genetic Polymorphisms
2.4. Genetic Differences between Non-Smoker and Smoker Breast Cancer Patients
2.5. Genetic Differences between Smoker Controls and Smoker Breast Cancer Patients
3. Discussion
4. Materials and Methods
4.1. Subject Enrolment and Data Collection
4.2. Genotyping
4.3. Statistical Analysis
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
- World Health Organization. Anonymous WHO urges more countries to require large, graphic health warnings on tobacco packaging: The WHO report on the global tobacco epidemic, 2011 examines anti-tobacco mass-media campaigns. Cent. Eur. J. Public Health 2011, 19, 1215–1216. [Google Scholar]
- Reynolds, P. Smoking and breast cancer. J. Mammary Gland Biol. Neoplasia 2013, 18, 15–23. [Google Scholar] [CrossRef] [PubMed]
- Terry, P.D.; Goodman, M. Is the association between cigarette smoking and breast cancer modified by genotype? A review of epidemiologic studies and meta-analysis. Cancer Epidemiol. Biomark. Prev. 2006, 15, 602–611. [Google Scholar] [CrossRef] [PubMed]
- Young, E.; Leatherdale, S.; Sloan, M.; Kreiger, N.; Barisic, A. Age of smoking initiation and risk of breast cancer in a sample of Ontario women. Tob. Induc. Dis. 2009. [Google Scholar] [CrossRef] [PubMed]
- Stephenson, N.; Beckmann, L.; Chang-Claude, J. Carcinogen metabolism, cigarette smoking, and breast cancer risk: A Bayes model averaging approach. Epidemiol. Perspect. Innov. 2010. [Google Scholar] [CrossRef] [PubMed]
- Gaudet, M.M.; Gapstur, S.M.; Sun, J.; Diver, W.R.; Hannan, L.M.; Thun, M.J. Active smoking and breast cancer risk: Original cohort data and meta-analysis. J. Natl. Cancer Inst. 2013, 105, 515–525. [Google Scholar] [CrossRef] [PubMed]
- Kasajova, P.; Holubekova, V.; Mendelova, A.; Lasabova, Z.; Zubor, P.; Kudela, E.; Biskupska-Bodova, K.; Danko, J. Active cigarette smoking and the risk of breast cancer at the level of N-acetyltransferase 2 (NAT2) gene polymorphisms. Tumour Biol. 2016, 37, 7929–7937. [Google Scholar] [CrossRef] [PubMed]
- Plant, A.L.; Benson, D.M.; Smith, L.C. Cellular uptake and intracellular localization of benzo(a)pyrene by digital fluorescence imaging microscopy. J. Cell Biol. 1985, 100, 1295–1308. [Google Scholar] [CrossRef] [PubMed]
- Di Cello, F.; Flowers, V.L.; Li, H.; Vecchio-Pagan, B.; Gordon, B.; Harbom, K.; Shin, J.; Beaty, R.; Wang, W.; Brayton, C.; et al. Cigarette smoke induces epithelial to mesenchymal transition and increases the metastatic ability of breast cancer cells. Mol. Cancer 2013. [Google Scholar] [CrossRef] [PubMed]
- Petrakis, N.L.; Gruenke, L.D.; Beelen, T.C.; Castagnoli, N., Jr.; Craig, J.C. Nicotine in breast fluid of nonlactating women. Science 1978, 199, 303–305. [Google Scholar] [CrossRef] [PubMed]
- Rundle, A.; Tang, D.; Zhou, J.; Cho, S.; Perera, F. The association between glutathione S-transferase M1 genotype and polycyclic aromatic hydrocarbon-DNA adducts in breast tissue. Cancer Epidemiol. Biomarkers Prev. 2000, 9, 1079–1085. [Google Scholar] [PubMed]
- Anderson, L.N.; Cotterchio, M.; Mirea, L.; Ozcelik, H.; Kreiger, N. Passive cigarette smoke exposure during various periods of life, genetic variants, and breast cancer risk among never smokers. Am. J. Epidemiol. 2012, 175, 289–301. [Google Scholar] [CrossRef] [PubMed]
- Andres, S.A.; Bickett, K.E.; Alatoum, M.A.; Kalbfleisch, T.S.; Brock, G.N.; Wittliff, J.L. Interaction between smoking history and gene expression levels impacts survival of breast cancer patients. Breast Cancer Res. Treat. 2015, 152, 545–556. [Google Scholar] [CrossRef] [PubMed]
- Cotterchio, M.; Mirea, L.; Ozcelik, H.; Kreiger, N. Active cigarette smoking, variants in carcinogen metabolism genes and breast cancer risk among pre- and post-menopausal women in Ontario, Canada. Breast J. 2014, 20, 468–480. [Google Scholar] [CrossRef] [PubMed]
- Cox, D.G.; Dostal, L.; Hunter, D.J.; le Marchand, L.; Hoover, R.; Ziegler, R.G.; Thun, M.J. Breast and Prostate Cancer Cohort Consortium: N-acetyltransferase 2 polymorphisms, tobacco smoking, and breast cancer risk in the breast and prostate cancer cohort consortium. Am. J. Epidemiol. 2011, 174, 1316–1322. [Google Scholar] [CrossRef] [PubMed]
- Verde, Z.; Reinoso, L.; Chicharro, L.M.; Resano, P.; Sanchez-Hernandez, I.; Rodriguez Gonzalez-Moro, J.M.; Bandres, F.; Gomez-Gallego, F.; Santiago, C. Are SNP-Smoking Association Studies Needed in Controls? DNA Repair Gene Polymorphisms and Smoking Intensity. PLoS ONE 2015, 10, e0129374. [Google Scholar] [CrossRef] [PubMed]
- Doll, R.; Peto, R. Cigarette smoking and bronchial carcinoma: Dose and time relationships among regular smokers and lifelong non-smokers. J. Epidemiol. Community Health 1978, 32, 303–313. [Google Scholar] [CrossRef] [PubMed]
- Godtfredsen, N.S.; Holst, C.; Prescott, E.; Vestbo, J.; Osler, M. Smoking reduction, smoking cessation, and mortality: A 16-year follow-up of 19,732 men and women from The Copenhagen Centre for Prospective Population Studies. Am. J. Epidemiol. 2002, 156, 994–1001. [Google Scholar] [CrossRef] [PubMed]
- Husten, C.G. How should we define light or intermittent smoking? Does it matter? Nicotine Tob. Res. 2009, 11, 111–121. [Google Scholar] [CrossRef] [PubMed]
- Park, S.J.; Yi, B.; Lee, H.S.; Oh, W.Y.; Na, H.K.; Lee, M.; Yang, M. To quit or not: Vulnerability of women to smoking tobacco. J. Environ. Sci. Health C Environ. Carcinog. Ecotoxicol. Rev. 2016, 34, 33–56. [Google Scholar] [CrossRef] [PubMed]
- Hecht, S.S. Cigarette smoking and lung cancer: Chemical mechanisms and approaches to prevention. Lancet Oncol. 2002, 3, 461–469. [Google Scholar] [CrossRef]
- Russo, A.L.; Thiagalingam, A.; Pan, H.; Califano, J.; Cheng, K.H.; Ponte, J.F.; Chinnappan, D.; Nemani, P.; Sidransky, D.; Thiagalingam, S. Differential DNA hypermethylation of critical genes mediates the stage-specific tobacco smoke-induced neoplastic progression of lung cancer. Clin. Cancer Res. 2005, 11, 2466–2470. [Google Scholar] [CrossRef] [PubMed]
- Marcus, P.M.; Hayes, R.B.; Vineis, P.; Garcia-Closas, M.; Caporaso, N.E.; Autrup, H.; Branch, R.A.; Brockmoller, J.; Ishizaki, T.; Karakaya, A.E.; et al. Cigarette smoking, N-acetyltransferase 2 acetylation status, and bladder cancer risk: A case-series meta-analysis of a gene-environment interaction. Cancer Epidemiol. Biomark. Prev. 2000, 9, 461–467. [Google Scholar]
- Li, D.; Walcott, F.L.; Chang, P.; Zhang, W.; Zhu, J.; Petrulis, E.; Singletary, S.E.; Sahin, A.A.; Bondy, M.L. Genetic and environmental determinants on tissue response to in vitro carcinogen exposure and risk of breast cancer. Cancer Res. 2002, 62, 4566–4570. [Google Scholar] [PubMed]
- Ali, K.; Mahjabeen, I.; Sabir, M.; Mehmood, H.; Kayani, M.A. OGG1 Mutations and Risk of Female Breast Cancer: Meta-Analysis and Experimental Data. Dis. Markers 2015, 2015, 690878. [Google Scholar] [CrossRef] [PubMed]
- Tyndale, R.F.; Sellers, E.M. Genetic variation in CYP2A6-mediated nicotine metabolism alters smoking behavior. Ther. Drug Monit. 2002, 24, 163–171. [Google Scholar] [CrossRef] [PubMed]
- Nebert, D.W.; Wikvall, K.; Miller, W.L. Human cytochromes P450 in health and disease. Philos. Trans. R Soc. Lond. B Biol. Sci. 2013, 368, 20120431. [Google Scholar] [CrossRef] [PubMed]
- McManus, M.E.; Burgess, W.M.; Veronese, M.E.; Huggett, A.; Quattrochi, L.C.; Tukey, R.H. Metabolism of 2-acetylaminofluorene and benzo(a)pyrene and activation of food-derived heterocyclic amine mutagens by human cytochromes P-450. Cancer Res. 1990, 50, 3367–3376. [Google Scholar] [PubMed]
- Lee, A.J.; Cai, M.X.; Thomas, P.E.; Conney, A.H.; Zhu, B.T. Characterization of the oxidative metabolites of 17β-estradiol and estrone formed by 15 selectively expressed human cytochrome p450 isoforms. Endocrinology 2003, 144, 3382–3398. [Google Scholar] [CrossRef] [PubMed]
- Monostory, K.; Dvorak, Z. Steroid regulation of drug-metabolizing cytochromes P450. Curr. Drug Metab. 2011, 12, 154–172. [Google Scholar] [CrossRef] [PubMed]
- Saquib, N.; Stefanick, M.L.; Natarajan, L.; Pierce, J.P. Mortality risk in former smokers with breast cancer: Pack-years vs. smoking status. Int. J. Cancer 2013, 133, 2493–2497. [Google Scholar] [CrossRef] [PubMed]
- Shizu, M.; Itoh, Y.; Sunahara, R.; Chujo, S.; Hayashi, H.; Ide, Y.; Takii, T.; Koshiko, M.; Chung, S.W.; Hayakawa, K.; et al. Cigarette smoke condensate upregulates the gene and protein expression of proinflammatory cytokines in human fibroblast-like synoviocyte line. J. Interferon Cytokine Res. 2008, 28, 509–521. [Google Scholar] [PubMed]
- Mitrunen, K.; Hirvonen, A. Molecular epidemiology of sporadic breast cancer. The role of polymorphic genes involved in oestrogen biosynthesis and metabolism. Mutat. Res. 2003, 544, 9–41. [Google Scholar] [PubMed]
- Miyoshi, Y.; Noguchi, S. Polymorphisms of estrogen synthesizing and metabolizing genes and breast cancer risk in Japanese women. Biomed. Pharmacother. 2003, 57, 471–481. [Google Scholar] [CrossRef] [PubMed]
- Ambrosone, C.B.; Freudenheim, J.L.; Marshall, J.R.; Graham, S.; Vena, J.E.; Brasure, J.R.; Michalek, A.M.; Laughlin, R.; Nemoto, T.; Shields, P.G. The association of polymorphic N-acetyltransferase (NAT2) with breast cancer risk. Ann. N. Y. Acad. Sci. 1995, 768, 250–252. [Google Scholar] [CrossRef] [PubMed]
- Ishibe, N.; Hankinson, S.E.; Colditz, G.A.; Spiegelman, D.; Willett, W.C.; Speizer, F.E.; Kelsey, K.T.; Hunter, D.J. Cigarette smoking, cytochrome P450 1A1 polymorphisms, and breast cancer risk in the Nurses’ Health Study. Cancer Res. 1998, 58, 667–671. [Google Scholar] [PubMed]
- Miyoshi, Y.; Takahashi, Y.; Egawa, C.; Noguchi, S. Breast cancer risk associated with CYP1A1 genetic polymorphisms in Japanese women. Breast J. 2002, 8, 209–215. [Google Scholar] [CrossRef] [PubMed]
- Bernauer, U.; Heinrich-Hirsch, B.; Tonnies, M.; Peter-Matthias, W.; Gundert-Remy, U. Characterisation of the xenobiotic-metabolizing Cytochrome P450 expression pattern in human lung tissue by immunochemical and activity determination. Toxicol. Lett. 2006, 164, 278–288. [Google Scholar] [CrossRef] [PubMed]
- Hafeez, S.; Ahmed, A.; Rashid, A.Z.; Kayani, M.A. Down-regulation of CYP1A1 expression in breast cancer. Asian Pac. J. Cancer Prev. 2012, 13, 1757–1760. [Google Scholar] [CrossRef] [PubMed]
- Kisselev, P.; Schunck, W.H.; Roots, I.; Schwarz, D. Association of CYP1A1 polymorphisms with differential metabolic activation of 17β-estradiol and estrone. Cancer Res. 2005, 65, 2972–2978. [Google Scholar] [CrossRef] [PubMed]
- Verde, Z.; Reinoso-Barbero, L.; Chicharro, L.; Garatachea, N.; Resano, P.; Sanchez-Hernandez, I.; Gonzalez-Moro, J.M.R.; Bandres, F.; Santiago, C.; Gomez-Gallego, F. Effects of cigarette smoking and nicotine metabolite ratio on leukocyte telomere length. Environ. Res. 2015, 140, 488–494. [Google Scholar] [CrossRef] [PubMed]
- Cox, L.A., Jr. Low-dose nonlinear effects of smoking on coronary heart disease risk. Dose. Response 2012, 10, 219–232. [Google Scholar] [CrossRef] [PubMed]
- Sorlie, T.; Perou, C.M.; Tibshirani, R.; Aas, T.; Geisler, S.; Johnsen, H.; Hastie, T.; Eisen, M.B.; van de Rijn, M.; Jeffrey, S.S.; et al. Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications. Proc. Natl. Acad. Sci. USA 2001, 98, 10869–10874. [Google Scholar] [CrossRef] [PubMed]
- Terry, P.D.; Rohan, T.E. Cigarette smoking and the risk of breast cancer in women: A review of the literature. Cancer Epidemiol. Biomark. Prev. 2002, 11, 953–971. [Google Scholar]
- Althuis, M.D.; Fergenbaum, J.H.; Garcia-Closas, M.; Brinton, L.A.; Madigan, M.P.; Sherman, M.E. Etiology of hormone receptor-defined breast cancer: A systematic review of the literature. Cancer Epidemiol. Biomark. Prev. 2004, 13, 1558–1568. [Google Scholar]
- Yoo, K.Y.; Tajima, K.; Miura, S.; Takeuchi, T.; Hirose, K.; Risch, H.; Dubrow, R. Breast cancer risk factors according to combined estrogen and progesterone receptor status: A case-control analysis. Am. J. Epidemiol. 1997, 146, 307–314. [Google Scholar] [CrossRef] [PubMed]
- Hunter, D.J.; Hankinson, S.E.; Hough, H.; Gertig, D.M.; Garcia-Closas, M.; Spiegelman, D.; Manson, J.E.; Colditz, G.A.; Willett, W.C.; Speizer, F.E.; et al. A prospective study of NAT2 acetylation genotype, cigarette smoking and risk of breast cancer. Carcinogenesis 1997, 18, 2127–2132. [Google Scholar] [CrossRef] [PubMed]
- Cooper, J.A.; Rohan, T.E.; Cant, E.L.; Horsfall, D.J.; Tilley, W.D. Risk factors for breast cancer by oestrogen receptor status: A population-based case-control study. Br. J. Cancer 1989, 59, 119–125. [Google Scholar] [CrossRef] [PubMed]
- Nishino, Y.; Minami, Y.; Kawai, M.; Fukamachi, K.; Sato, I.; Ohuchi, N.; Kakugawa, Y. Cigarette smoking and breast cancer risk in relation to joint estrogen and progesterone receptor status: A case-control study in Japan. Springerplus 2014, 3. [Google Scholar] [CrossRef] [PubMed]
- NCI-NHGRI Working Group on Replication in Association Studies; Chanock, S.J.; Manolio, T.; Boehnke, M.; Boerwinkle, E.; Hunter, D.J.; Thomas, G.; Hirschhorn, J.N.; Abecasis, G.; Altshuler, D.; et al. Replicating genotype-phenotype associations. Nature 2007, 447, 655–660. [Google Scholar]
- Garte, S.; Gaspari, L.; Alexandrie, A.K.; Ambrosone, C.; Autrup, H.; Autrup, J.L.; Baranova, H.; Bathum, L.; Benhamou, S.; Boffetta, P.; et al. Metabolic gene polymorphism frequencies in control populations. Cancer Epidemiol. Biomark. Prev. 2001, 10, 1239–1248. [Google Scholar]
Variables | Breast Carcinoma Group | Healthy Group | ||
---|---|---|---|---|
Non-Smokers | Smokers | Smokers | ||
Age (years) | 64 ± 10 | 56 ± 9 | 42 ± 11 | |
Age at diagnosis (years) | 56 ± 11 | 48 ± 9 | - | |
Breast cancer before age 45 years (%) | 19.7% | 41.3% | - | |
Smoking duration (years) | - | 25.5 ± 11.4 | 22.9 ± 11.8 | |
Age at initiation (years) | - | 18 ± 5 | 18 ± 5 | |
CPD | - | 14.0 ± 8.7 | 19.3 ± 13.1 | |
PYS | - | 17.2 ± 13.8 | 25.5 ± 27.4 | |
Heavy smokers 15 ≥ PYS (%) | - | 47.9% | 55.0% | |
Breast cancer histology | In situ carcinoma (%) | 22.9% | 14.6% | - |
Invasive (infiltrating carcinoma) (%) | 77.1% | 85.4% | - |
Genotype | Breast Cancer Patients | |||
---|---|---|---|---|
Non-Smokers | Smokers | p | OR (95% CI) | |
XRCC1 Arg399Gln | ||||
Arg/Arg, Arg/Gln a | 78.3 | 75.7 | 0.413 | 1.15 (0.57–2.31) |
Gln/Gln | 21.7 | 24.3 | ||
APEX1 Asp148Glu | ||||
Asp/Asp, Asp/Glu a | 75.0 | 67.9 | 0.192 | 0.78 (0.48–1.26) |
Glu/Glu | 25.0 | 32.1 | ||
XRCC3 Thr241Met | ||||
Thr/Thr, Thr/Mer a | 70.4 | 71.0 | 0.528 | 1.02 (0.65–1.59) |
Met/Met | 29.6 | 29.0 | ||
ERCC2 Asp312Asn | ||||
Asp/Asp, Asp/Asn a | 85.9 | 85.6 | 0.565 | 0.97 (0.48–1.99) |
Asn/Asn | 14.1 | 14.4 | ||
KLC3 Lys751Gln | ||||
Lys/Lys, Lys/Gln a | 83.6 | 81.7 | 0.452 | 0.89 (0.47–1.72) |
Gln/Gln | 16.4 | 18.3 | ||
CYP1A1 Ile462Val | ||||
Ile/Ile a | 95.9 | 94.9 | 0.511 | 0.79 (0.21–2.98) |
Ile/Val | 4.1 | 5.1 | ||
CYP2A6 Lys160His | ||||
Lys/Lys | 100 | 93 | 0.039 | 1.07 (1.02–1.13) |
Lys/His a | 0 | 7 | ||
CYP2A6 –48T > G | ||||
TT/TG a | 87 | 85.5 | 0.494 | 0.89 (0.39–2.03) |
GG | 13 | 14.3 |
Genotype | Smokers Group | |||
---|---|---|---|---|
Breast Cancer Group | Healthy Group | p | OR (95% CI) | |
XRCC1 Arg399Gln | ||||
Arg/Arg, Arg/Gln a | 75.7 | 82.3 | 0.172 | 1.37 (0.78–2.40) |
Gln/Gln | 24.3 | 17.7 | ||
APEX1 Asp148Glu | ||||
Asp/Asp, Asp/Glu a | 67.9 | 66.7 | 0.483 | 0.96 (0.64–1.44) |
Glu/Glu | 32.1 | 33.3 | ||
XRCC3 Thr241Met | ||||
Thr/Thr, Thr/Mer a | 71.0 | 87.7 | 0.003 | 2.89 (1.35–6.21) |
Met/Met | 29.0 | 12.3 | ||
ERCC2 Asp312Asn | ||||
Asp/Asp, Asp/Asn a | 85.6 | 87.5 | 0.432 | 1.15 (0.56–2.35) |
Asn/Asn | 14.4 | 12.5 | ||
KLC3 Lys751Gln | ||||
Lys/Lys, Lys/Gln a | 81.7 | 86.2 | 0.283 | 1.32 (0.65–2.68) |
Gln/Gln | 18.3 | 13.8 | ||
CYP1A1 Ile462Val | ||||
Ile/Ile | 94.9 | 78.5 | 0.001 | 5.09 (1.94–13.36) |
Ile/Val a | 5.1 | 21.5 | ||
CYP2A6 Lys160His | ||||
Lys/Lys a | 93 | 91.4 | 0.460 | 0.81 (0.28–2.37) |
Lys/His | 7 | 8.6 | ||
CYP2A6 –48T>G | ||||
TT/TG a | 85.5 | 83.3 | 0.437 | 0.87 (0.42–1.80) |
GG | 14.3 | 16.7 |
Genotype | Years Smoking < 20 | Years Smoking ≥ 20 | ||||||
---|---|---|---|---|---|---|---|---|
Breast Cancer Group | Healthy Group | p | OR (95% CI) | Breast Cancer Group | Healthy Group | p | OR (95% CI) | |
XRCC1 Arg399Gln | ||||||||
Arg/Arg, Arg/Gln a | 65.0 | 87.9 | 0.022 | 2.88 (1.05–7.93) | 80.4 | 77.8 | 0.440 | 0.88 (0.44–1.74) |
Gln/Gln | 35.0 | 12.1 | 19.6 | 22.2 | ||||
APEX1 Asp148Glu | ||||||||
Asp/Asp, Asp/Glu a | 74.4 | 78.1 | 0.466 | 1.17 (0.50–2.73) | 62.5 | 57.8 | 0.258 | 0.82 (0.53–1.29) |
Glu/Glu | 25.6 | 21.9 | 34.8 | 42.2 | ||||
XRCC3 Thr241Met | ||||||||
Thr/Thr, Thr/Mer a | 69.2 | 87.9 | 0.052 | 2.5 (0.90–7.13) | 73.0 | 89.4 | 0.020 | 2.53 (1.03–6.21) |
Met/Met | 30.8 | 12.1 | 27.0 | 10.6 | ||||
ERCC2 Asp312Asn | ||||||||
Asp/Asp, Asp/Asn a | 86.8 | 84.8 | 0.538 | 0.87 (0.27–2.74) | 85.6 | 89.1 | 0.385 | 1.32 (0.50–3.50) |
Asn/Asn | 13.2 | 15.2 | 14.4 | 10.9 | ||||
KLC3 Lys751Gln | ||||||||
Lys/Lys, Lys/Gln a | 82.1 | 78.6 | 0.479 | 0.83 (0.31–2.22) | 81.8 | 91.7 | 0.132 | 2.18 (0.67–7.03) |
Gln/Gln | 17.9 | 21.4 | 18.2 | 8.3 | ||||
CYP1A1 Ile462Val | ||||||||
Ile/Ile | 92.5 | 83.9 | 0.222 | 1.10 (0.92–1.32) | 95.7 | 75.8 | 0.002 | 7.12 (1.98–25.59) |
Ile/Val a | 7.5 | 16.1 | 4.3 | 24.2 | ||||
CYP2A6 Lys160His | ||||||||
Lys/Lys a | 96.9 | 90.0 | 0.282 | 0.31 (0.03–2.84) | 92.4 | 92.6 | 0.670 | 1.02 (0.22–4.78) |
Lys/His | 3.1 | 10.0 | 7.6 | 7.4 | ||||
CYP2A6−48T > G | ||||||||
TT/TG a | 84.4 | 87.5 | 0.500 | 1.25 (0.37–4.23) | 86.7 | 77.8 | 0.214 | 0.60 (0.24–1.49) |
GG | 15.6 | 12.5 | 13.3 | 22.2 |
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Verde, Z.; Santiago, C.; Chicharro, L.M.; Reinoso-Barbero, L.; Tejerina, A.; Bandrés, F.; Gómez-Gallego, F. Effect of Genetic Polymorphisms and Long-Term Tobacco Exposure on the Risk of Breast Cancer. Int. J. Mol. Sci. 2016, 17, 1726. https://doi.org/10.3390/ijms17101726
Verde Z, Santiago C, Chicharro LM, Reinoso-Barbero L, Tejerina A, Bandrés F, Gómez-Gallego F. Effect of Genetic Polymorphisms and Long-Term Tobacco Exposure on the Risk of Breast Cancer. International Journal of Molecular Sciences. 2016; 17(10):1726. https://doi.org/10.3390/ijms17101726
Chicago/Turabian StyleVerde, Zoraida, Catalina Santiago, Luis Miguel Chicharro, Luis Reinoso-Barbero, Alejandro Tejerina, Fernando Bandrés, and Félix Gómez-Gallego. 2016. "Effect of Genetic Polymorphisms and Long-Term Tobacco Exposure on the Risk of Breast Cancer" International Journal of Molecular Sciences 17, no. 10: 1726. https://doi.org/10.3390/ijms17101726
APA StyleVerde, Z., Santiago, C., Chicharro, L. M., Reinoso-Barbero, L., Tejerina, A., Bandrés, F., & Gómez-Gallego, F. (2016). Effect of Genetic Polymorphisms and Long-Term Tobacco Exposure on the Risk of Breast Cancer. International Journal of Molecular Sciences, 17(10), 1726. https://doi.org/10.3390/ijms17101726