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Mak PJ, Gregory MC, Sligar SG, Kincaid JR. Resonance Raman spectroscopy reveals that substrate structure selectively impacts the heme-bound diatomic ligands of CYP17. Biochemistry 2014; 53:90-100. [PMID: 24328388 PMCID: PMC3922198 DOI: 10.1021/bi4014424] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An important function of steroidogenic cytochromes P450 is the transformation of cholesterol to produce androgens, estrogens, and the corticosteroids. The activities of cytochrome P450c17 (CYP17) are essential in sex hormone biosynthesis, with severe developmental defects being a consequence of deficiency or mutations. The first reaction catalyzed by this multifunctional P450 is the 17α-hydroxylation of pregnenolone (PREG) to 17α-hydroxypregnenolone (17-OH PREG) and progesterone (PROG) to 17α-hydroxyprogesterone (17-OH PROG). The hydroxylated products then either are used for production of corticoids or undergo a second CYP17 catalyzed transformation, representing the first committed step of androgen formation. While the hydroxylation reactions are catalyzed by the well-known Compound I intermediate, the lyase reaction is believed to involve nucleophilic attack of the earlier peroxo- intermediate on the C20-carbonyl. Herein, resonance Raman (rR) spectroscopy reveals that substrate structure does not impact heme structure for this set of physiologically important substrates. On the other hand, rR spectra obtained here for the ferrous CO adducts with these four substrates show that substrates do interact differently with the Fe-C-O fragment, with large differences between the spectra obtained for the samples containing 17-OH PROG and 17-OH PREG, the latter providing evidence for the presence of two Fe-C-O conformers. Collectively, these results demonstrate that individual substrates can differentially impact the disposition of a heme-bound ligand, including dioxygen, altering the reactivity patterns in such a way as to promote preferred chemical conversions, thereby avoiding the profound functional consequences of unwanted side reactions.
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Affiliation(s)
- Piotr J. Mak
- Department of Chemistry, Marquette University, Milwaukee, WI 53233
| | | | - Stephen G. Sligar
- Department of Biochemistry, University of Illinois, Urbana, IL, 61801
- Department of Chemistry, University of Illinois, Urbana, IL, 61801
- College of Medicine, University of Illinois, Urbana, IL, 61801
| | - James R. Kincaid
- Department of Chemistry, Marquette University, Milwaukee, WI 53233
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Ryan CJ, Smith MR, de Bono JS, Molina A, Logothetis CJ, de Souza P, Fizazi K, Mainwaring P, Piulats JM, Ng S, Carles J, Mulders PFA, Basch E, Small EJ, Saad F, Schrijvers D, Van Poppel H, Mukherjee SD, Suttmann H, Gerritsen WR, Flaig TW, George DJ, Yu EY, Efstathiou E, Pantuck A, Winquist E, Higano CS, Taplin ME, Park Y, Kheoh T, Griffin T, Scher HI, Rathkopf DE. Abiraterone in metastatic prostate cancer without previous chemotherapy. N Engl J Med 2013; 368:138-48. [PMID: 23228172 PMCID: PMC3683570 DOI: 10.1056/nejmoa1209096] [Citation(s) in RCA: 2020] [Impact Index Per Article: 183.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Abiraterone acetate, an androgen biosynthesis inhibitor, improves overall survival in patients with metastatic castration-resistant prostate cancer after chemotherapy. We evaluated this agent in patients who had not received previous chemotherapy. METHODS In this double-blind study, we randomly assigned 1088 patients to receive abiraterone acetate (1000 mg) plus prednisone (5 mg twice daily) or placebo plus prednisone. The coprimary end points were radiographic progression-free survival and overall survival. RESULTS The study was unblinded after a planned interim analysis that was performed after 43% of the expected deaths had occurred. The median radiographic progression-free survival was 16.5 months with abiraterone-prednisone and 8.3 months with prednisone alone (hazard ratio for abiraterone-prednisone vs. prednisone alone, 0.53; 95% confidence interval [CI], 0.45 to 0.62; P<0.001). Over a median follow-up period of 22.2 months, overall survival was improved with abiraterone-prednisone (median not reached, vs. 27.2 months for prednisone alone; hazard ratio, 0.75; 95% CI, 0.61 to 0.93; P=0.01) but did not cross the efficacy boundary. Abiraterone-prednisone showed superiority over prednisone alone with respect to time to initiation of cytotoxic chemotherapy, opiate use for cancer-related pain, prostate-specific antigen progression, and decline in performance status. Grade 3 or 4 mineralocorticoid-related adverse events and abnormalities on liver-function testing were more common with abiraterone-prednisone. CONCLUSIONS Abiraterone improved radiographic progression-free survival, showed a trend toward improved overall survival, and significantly delayed clinical decline and initiation of chemotherapy in patients with metastatic castration-resistant prostate cancer. (Funded by Janssen Research and Development, formerly Cougar Biotechnology; ClinicalTrials.gov number, NCT00887198.).
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Affiliation(s)
- Charles J Ryan
- Genitourinary Medical Oncology Program, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94115, USA.
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3
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Abstract
Abiraterone acetate is an orally administered potent inhibitor of cytochrome P450, family 17, subfamily A, polypeptide 1 (CYP17), which is essential for synthesis of testosterone from cholesterol. Although decreasing serum testosterone through inhibition of testicular function is the first line of treatment for men with metastatic prostate cancer, residual androgens may still be detected in patients treated with luteinizing hormone-releasing hormone agonists or antagonists. Treatment with abiraterone results in rapid, and complete, inhibition of androgen synthesis in the adrenal glands and potentially within the tumor itself. An overall survival benefit of maximal androgen suppression was recently shown in a randomized placebo-controlled phase III clinical trial of abiraterone with prednisone versus prednisone in men with metastatic castrate-resistant prostate cancer previously treated with docetaxel chemotherapy. Abiraterone's efficacy shows the importance of androgen signaling in patients with castrate-resistant metastatic disease, with additional confirmation from recent studies of other novel agents such as MDV3100, an androgen receptor signaling inhibitor. These promising results now pose a new angle to an old problem about hormonal therapy and raise new questions about how resistance develops, how to best sequence therapy, and how to optimize combinations with other emerging novel agents.
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Affiliation(s)
- Mark N Stein
- Cancer Institute of NewJersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
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Abstract
OBJECTIVE Cytochrome P450 17alpha-hydroxylases-C-(17,20)-lyase (CYP17) is a key enzyme involved with the androgen biosynthesis pathway and has recently been targeted for therapy in men with advanced prostate cancer (PCa). However, studies relating prostate cancer outcomes with CYP17 gene variants have conflicting results. In this study we analyzed Single Nucleotide Polymorphisms (SNPs) spanning the CYP17 gene for association with PCa survival. METHODS The cohort was comprised of Caucasian men, aged 40-64, diagnosed with PCa between 1993 and 1996 in King County, Washington who participated in a population-based case-control study. CYP17 SNPs were selected to capture variation across the gene and known regulatory regions. PCa-specific mortality (PCSM) was obtained by linking to the SEER cancer registry. Recurrence/progression of PCa was determined from patient survey data and medical records. Cox proportional hazards regression analysis was used to generate hazard ratios for patient outcomes. RESULTS Genotypes were available for 598 cases. With a median follow-up of 13.2 years, 44 PCa deaths were observed. Recurrence/progression events were observed in 30% of subjects. No genetic association with disease progression were identified. However, men with the variant A allele in rs10883783 had a 56% risk reduction in PCSM (HR 0.44, 95% CI 0.21-0.98). CONCLUSION These data suggest that genetic variation in the CYP17 gene in Caucasian men is associated with PCa survival.
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Affiliation(s)
- Jonathan L Wright
- Department of Urology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
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SIVILS JEFFREYC, GONZALEZ IVEN, BAIN LISAJ. Mice lacking Mrp1 have reduced testicular steroid hormone levels and alterations in steroid biosynthetic enzymes. Gen Comp Endocrinol 2010; 167:51-9. [PMID: 20178799 PMCID: PMC2862834 DOI: 10.1016/j.ygcen.2010.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
Abstract
The multidrug resistance-associated protein 1 (MRP1/ABCC1) is a member of the ABC active transporter family that can transport several steroid hormone conjugates, including 17beta-estradiol glucuronide, dehydroepiandrosterone sulfate (DHEAS), and estrone 3-sulfate. The present study investigated the role that MRP1 plays in maintaining proper hormone levels in the serum and testes. Serum and testicular steroid hormone levels were examined in both wild-type mice and Mrp1 null mice. Serum testosterone levels were reduced 5-fold in mice lacking Mrp1, while testicular androstenedione, testosterone, estradiol, and dehydroepiandrosterone (DHEA) were significantly reduced by 1.7- to 4.5-fold in Mrp1 knockout mice. Investigating the mechanisms responsible for the reduction in steroid hormones in Mrp1-/- mice revealed no differences in the expression or activity of enzymes that inactivate steroids, the sulfotransferases or glucuronosyltransferases. However, steroid biosynthetic enzyme levels in the testes were altered. Cyp17 protein levels were increased by 1.6-fold, while Cyp17 activity using progesterone as a substrate was also increased by 1.4- to 2.0-fold in mice lacking Mrp1. Additionally, the ratio of 17beta-hydroxysteroid dehydrogenase to 3beta-hydroxysteroid dehydrogenase, and steroidogenic factor 1 to 3beta-hydroxysteroid dehydrogenase were significantly increased in the testes of Mrp1-/- mice. These results indicate that Mrp1-/- mice have lowered steroid hormones levels, and suggests that upregulation of steroid biosynthetic enzymes may be an attempt to maintain proper steroid hormone homeostasis.
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Affiliation(s)
- JEFFREY C. SIVILS
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - IVEN GONZALEZ
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - LISA J. BAIN
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Address correspondence to: Lisa Bain, Clemson University, 132 Long Hall, Clemson, SC 29634. Phone: 1-864-656-5050; FAX: 1-864- 656-0435;
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Abstract
Optimal steroid hormone biosynthesis occurs via the integration of multiple regulatory processes, one of which entails a coordinate increase in the transcription of all genes required for steroidogenesis. In the human adrenal cortex adrenocorticotropin (ACTH) activates a signaling cascade that promotes the dynamic assembly of protein complexes on the promoters of steroidogenic genes. For CYP17, multiple transcription factors, including steroidogenic factor-1 (SF-1), GATA-6, and sterol regulatory binding protein 1 (SREBP1), are recruited to the promoter during activated transcription. The ability of these factors to increase CYP17 mRNA expression requires the formation of higher order coregulatory complexes, many of which contain enzymatic activities that post-translationally modify both the transcription factors and histones. We discuss the mechanisms by which transcription factors and coregulatory proteins regulate CYP17 transcription and summarize the role of kinases, phosphatases, acetyltransferases, and histone deacetylases in controlling CYP17 mRNA expression.
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Affiliation(s)
- Marion B Sewer
- School of Biology and the Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, United States.
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Sewer MB, Li D, Dammer EB, Jagarlapudi S, Lucki N. Multiple Signaling Pathways Coordinate CYP17 Gene Expression in the Human Adrenal Cortex. Acta Chim Slov 2008; 55:53-57. [PMID: 20098627 PMCID: PMC2809372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Optimal levels of steroid hormone biosynthesis are assured by the integration of several regulatory mechanisms, including substrate delivery, enzymatic activity, and gene transcription. In the human adrenal cortex, optimal glucocorticoid secretion is achieved by the actions of adrenocorticotropin (ACTH), which exerts transcriptional pressure on all genes involved in steroidogenesis. One of these genes is CYP17, which encodes P450 17alpha-hydroxylase-17,20 lyase, a key enzyme in the production of cortisol and adrenal androgens. Levels of CYP17 transcription are regulated by multiple regulatory mechanisms that act to respond to various signaling cues. These cues are coordinated in a developmental, species-, and tissue-specific manner, with an additional time/circadian-dependent level of regulation. This brief review will highlight some of the signal transduction cascades and transcription factors that have been shown to modulate CYP17 gene expression in the adrenal cortex.
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Pattison JC, Saltzman W, Abbott DH, Hogan BK, Nguyen AD, Husen B, Einspanier A, Conley AJ, Bird IM. Gender and gonadal status differences in zona reticularis expression in marmoset monkey adrenals: Cytochrome b5 localization with respect to cytochrome P450 17,20-lyase activity. Mol Cell Endocrinol 2007; 265-266:93-101. [PMID: 17222503 PMCID: PMC1839875 DOI: 10.1016/j.mce.2006.12.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neonatal marmosets express an adrenal fetal zone comparable to humans. While adult males fail to express a functional ZR, with barely detectable blood DHEA levels, females produce higher levels of DHEA than males in adulthood. We investigated the presence of a putative functional ZR in adult female marmosets. In contrast to males, immunohistochemical analysis showed the ZR marker cytochrome b5 was elevated in the innermost zone in cycling females (compared to testis-intact males), further elevated in the adrenals from anovulatory females, and substantially elevated and continuous in ovariectomized females. As a functional test in vivo, following overnight dexamethasone treatment, cycling and anovulatory females showed higher levels of DHEA relative to males, but DHEA failed to increase in response to ACTH. In direct contrast, while ovariectomized females exhibited lower initial DHEA levels, clear increases were detectable after ACTH administration (p<0.05), suggesting an adrenal origin. The apparent differences in cytochrome b5 expression between groups were also further verified by Western blotting of adrenal microsomes, and compared to 17,20-lyase activity; the two parameters were positively correlated (p<0.01) across multiple treatment groups. We conclude that the cycling female marmoset expresses a rudimentary ZR with at least a capacity for DHEA production that becomes significantly ACTH-responsive after anovulation. Expression of cytochrome b5 in this region may be directly or indirectly controlled by gonadal function, and is, at least in part, a critical determinant in the development of an adrenal ZR that is more defined and significantly ACTH-responsive.
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Affiliation(s)
- J Christina Pattison
- Perinatal Research Laboratories, University of Wisconsin-Madison, Madison, WI 53715, USA
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Abstract
Steroidogenic factor (SF1, NR5A1, Ad4BP) is an orphan nuclear receptor that is essential for steroid hormone-biosynthesis and endocrine development. Studies have found that the ability of this receptor to increase target gene expression can be regulated by post-translational modification, subnuclear localization, and protein-protein interactions. Recent crystallographic studies and our mass spectrometric analyses of the endogenous receptor have demonstrated an integral role for ligand-binding in the control of SF1 transactivation activity. Herein, we discuss our findings that sphingosine is an endogenous ligand for SF1. These studies and the structural findings of others have demonstrated that the receptor can bind both sphingolipids and phospholipids. Thus, it is likely that multiple bioactive lipids are ligands for SF1 and that these lipids will differentially act to control SF1 activity in a context-dependent manner. Finally, these findings highlight a central role for bioactive lipids as mediators of trophic hormone-stimulated steroid hormone biosynthesis.
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Affiliation(s)
- Aarti N Urs
- School of Biology and the Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332-0230, United States
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Ahsan H, Whittemore AS, Chen Y, Senie RT, Hamilton SP, Wang Q, Gurvich I, Santella RM. Variants in estrogen-biosynthesis genes CYP17 and CYP19 and breast cancer risk: a family-based genetic association study. Breast Cancer Res 2004; 7:R71-81. [PMID: 15642171 PMCID: PMC1064100 DOI: 10.1186/bcr951] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Revised: 09/02/2004] [Accepted: 09/29/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Case-control studies have reported inconsistent results concerning breast cancer risk and polymorphisms in genes that control endogenous estrogen biosynthesis. We report findings from the first family-based association study examining associations between female breast cancer risk and polymorphisms in two key estrogen-biosynthesis genes CYP17 (T-->C promoter polymorphism) and CYP19 (TTTA repeat polymorphism). METHODS We conducted the study among 278 nuclear families containing one or more daughters with breast cancer, with a total of 1123 family members (702 with available constitutional DNA and questionnaire data and 421 without them). These nuclear families were selected from breast cancer families participating in the Metropolitan New York Registry, one of the six centers of the National Cancer Institute's Breast Cancer Family Registry. We used likelihood-based statistical methods to examine allelic associations. RESULTS We found the CYP19 allele with 11 TTTA repeats to be associated with breast cancer risk in these families. We also found that maternal (but not paternal) carrier status of CYP19 alleles with 11 repeats tended to be associated with breast cancer risk in daughters (independently of the daughters' own genotype), suggesting a possible in utero effect of CYP19. We found no association of a woman's breast cancer risk either with her own or with her mother's CYP17 genotype. CONCLUSION This family-based study indicates that a woman's personal and maternal carrier status of CYP19 11 TTTA repeat allele might be related to increased breast cancer risk. However, because this is the first study to report an association between CYP19 11 TTTA repeat allele and breast cancer, and because multiple comparisons have been made, the associations should be interpreted with caution and need confirmation in future family-based studies.
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Affiliation(s)
- Habibul Ahsan
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Alice S Whittemore
- Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California, USA
| | - Yu Chen
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Ruby T Senie
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Steven P Hamilton
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, New York USA
| | - Qiao Wang
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Irina Gurvich
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Regina M Santella
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA
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Gudmundsdottir K, Thorlacius S, Jonasson JG, Sigfusson BF, Tryggvadottir L, Eyfjord JE. CYP17 promoter polymorphism and breast cancer risk in males and females in relation to BRCA2 status. Br J Cancer 2003; 88:933-6. [PMID: 12644832 PMCID: PMC2377070 DOI: 10.1038/sj.bjc.6600839] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A T-C polymorphism in the promoter region of the CYP17 gene has been associated with male and female breast cancer risk as well as early-onset familial breast cancer. The potential role of this polymorphism was investigated in relation to breast cancer risk in Icelandic male and female carriers and noncarriers of a BRCA2 mutation. The study population consisted of 39 male and 523 female breast cancer cases and 309 male and 395 female controls. Of the cases, 15 males and 55 females carried a BRCA2 mutation. We did not find a significant association between male breast cancer risk and CYP17 genotypes. Among male breast cancer cases, the frequency of the CC genotype was higher among carriers of the 999del5 mutation (33.3%) than noncarriers (16.7%), although this difference also did not reach a statistical significance. No association was observed with breast cancer risk among females irrespective of menopausal status, stage of the disease or BRCA2 status. Our findings do not indicate a role for the CYP17 T-C polymorphism in female breast cancer, but a role in male carriers of a BRCA2 mutation could not be excluded because of the small sample size.
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Affiliation(s)
- K Gudmundsdottir
- Molecular and Cell Biology Research Laboratory, Icelandic Cancer Society, 125-Reykjavik, Iceland
| | - S Thorlacius
- Iceland Genomics Corporation, Reykjavik, Iceland
| | - J G Jonasson
- Cancer Registry, Icelandic Cancer Society, 125-Reykjavik, Iceland
- Department of Pathology, University Hospital, Reykjavik, Iceland
| | - B F Sigfusson
- Cancer Detection Clinic, Icelandic Cancer Society, 125-Reykjavik, Iceland
| | - L Tryggvadottir
- Cancer Registry, Icelandic Cancer Society, 125-Reykjavik, Iceland
| | - J E Eyfjord
- Molecular and Cell Biology Research Laboratory, Icelandic Cancer Society, 125-Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Molecular and Cell Biology Research Laboratory, Icelandic Cancer Society, PO Box 5420, 125 Reykjavik, Iceland. E-mail:
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Hamajima N, Iwata H, Obata Y, Matsuo K, Mizutani M, Iwase T, Miura S, Okuma K, Ohashi K, Tajima K. No association of the 5' promoter region polymorphism of CYP17 with breast cancer risk in Japan. Jpn J Cancer Res 2000; 91:880-5. [PMID: 11011114 PMCID: PMC5926442 DOI: 10.1111/j.1349-7006.2000.tb01029.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
To examine the association between breast cancer risk and a T-to-C substitution polymorphism at the 5' promoter region of CYP17, a case-control study was conducted at Aichi Cancer Center Hospital in Japan. Subjects were 144 histologically confirmed breast cancer patients diagnosed in the past 4 years and 166 hospital controls without cancer. Allele frequency among controls was 44.9% (95% confidence interval; 39.5 - 50.2) for C allele. Odds ratio (OR) of the polymorphism relative to TT-genotype was 0.97 (0.58 - 1.64) for TC-genotype and 0.81 (0.39 - 1.68) for CC-genotype. Subgroup analyses revealed that the OR was not statistically significant for the subgroups stratified by interval after diagnosis, age at menarche, age at first birth, menopausal status, body mass index, and mother / sisters' history of breast cancer. Consistent with previous studies conducted in other countries, the 5' promoter region polymorphism of CYP17 affected breast cancer risk of Japanese women to a limited extent. Although this is not a large-scale case-control study with population controls, these findings provide enough information to discourage further studies on the association between this polymorphism and breast cancer risk in Japan at large, and suggest that this polymorphism is useless for breast cancer risk estimation.
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Affiliation(s)
- N Hamajima
- Division of Epidemiology and Prevention, Aichi Cancer Center, Chikusa-ku, Nagoya 464-8681, Japan.
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