INTRODUCTION: We have previously shown that a tag single nucleotide polymorphism (rs10235235), which maps to the CYP3A locus (7q22.1), was associated with a reduction in premenopausal urinary estrone glucuronide levels and a modest reduction in risk of breast cancer in women age ≤50 years. METHODS: We further investigated the association of rs10235235 with breast cancer risk in a large case control study of 47,346 cases and 47,570 controls from 52 studies participating in the Breast Cancer Association Consortium. Genotyping of rs10235235 was conducted using a custom Illumina Infinium array. Stratified analyses were conducted to determine whether this association was modified by age at diagnosis, ethnicity, age at menarche or tumor characteristics. RESULTS: We confirmed the association of rs10235235 with breast cancer risk for women of European ancestry but found no evidence that this association differed with age at diagnosis. Heterozygote and homozygote odds ratios (ORs) were OR = 0.98 (95% CI 0.94, 1.01; P = 0.2) and OR = 0.80 (95% CI 0.69, 0.93; P = 0.004), respectively (P(trend) = 0.02). There was no evidence of effect modification by tumor characteristics. rs10235235 was, however, associated with age at menarche in controls (P(trend) = 0.005) but not cases (P(trend) = 0.97). Consequently the association between rs10235235 and breast cancer risk differed according to age at menarche (P(het) = 0.02); the rare allele of rs10235235 was associated with a reduction in breast cancer risk for women who had their menarche age ≥15 years (OR(het) = 0.84, 95% CI 0.75, 0.94; OR(hom) = 0.81, 95% CI 0.51, 1.30; P(trend) = 0.002) but not for those who had their menarche age ≤11 years (OR(het) = 1.06, 95% CI 0.95, 1.19, OR(hom) = 1.07, 95% CI 0.67, 1.72; P(trend) = 0.29). CONCLUSIONS: To our knowledge rs10235235 is the first single nucleotide polymorphism to be associated with both breast cancer risk and age at menarche consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. These associations are likely mediated via an effect on circulating hormone levels.

• MeSH
• běloši MeSH
• cytochrom P-450 CYP3A genetika   MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• genetické asociační studie * MeSH
• genotyp MeSH
• jednonukleotidový polymorfismus MeSH
• lidé středního věku MeSH
• lidé MeSH
• menarche genetika   MeSH
• nádory prsu genetika   patologie   MeSH
• premenopauza genetika   MeSH
• reprodukční anamnéza MeSH
• rizikové faktory MeSH
• senioři MeSH
• věk při počátku nemoci MeSH
• věkové faktory MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH

D-type cyclins are proto-oncogenic cell cycle regulators implicated in the pathogenesis of several types of cancer. Amplification of the cyclin D1 gene has been described in 30-50% of human head and neck squamous cell carcinoma (HNSCC). Using immunohistochemistry on archival specimens of human HNSCC and a mAb DCS-6, which is specific for cyclin D1, strong positivity was found in nuclei of 9 (17%) of 52, a moderately elevated signal in 16 (31%) of 52, and weak staining comparable with normal tissues in 27 (52%) of 52 patients. Immunoblotting analysis of five HNSCC-derived cell lines showed three distinct spectra of D-type cyclin proteins: cyclin D1 only (in UMSCC-2 and UMSCC-22b cell lines with 11q13 amplification), cyclins D1 and D3 (in HN5 and HN6), or cyclins D1, D2, and D3 (in UMSCC-1). Electroporation of neutralizing antibodies demonstrated requirement for cyclin D1 in cell cycle progression of all five HNSCC cell lines. Cyclin D2 was essential and showed a cooperative effect with cyclin D1 in positive regulation of G1 in UMSCC-1 cells. These data are consistent with the proposed oncogenic role of cyclin D1 in HNSCC and open up the way for immunohistochemical assessment of cyclin D1 aberrations in archival clinical specimens. It is also suggested that excessive levels of cyclin D1 alone or cooperative effects of several D-type cyclin proteins may lead to deregulation of G1 control in distinct subsets of human HNSCC. These results are discussed in the context of possible functional redundancy of D-type cyclins and the role of the D-type cyclin/p16-CDKN2/pRB pathway in tumorigenesis.

• MeSH
• cyklin D1 MeSH
• cyklin D2 MeSH
• cykliny analýza   fyziologie   MeSH
• G1 fáze * fyziologie   MeSH
• imunohistochemie MeSH
• lidé MeSH
• nádory hlavy a krku chemie   patologie   MeSH
• onkogenní proteiny analýza   fyziologie   MeSH
• spinocelulární karcinom chemie   patologie   MeSH
• zalévání tkání do parafínu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

The product of the retinoblastoma susceptibility gene, pRb, acts as a tumor suppressor and loss of its function is involved in the development of various types of cancer. DNA tumor viruses are supposed to disturb the normal regulation of the cell cycle by inactivating pRb. However, a direct function of pRb in regulation of the cell cycle has hitherto not been shown. We demonstrate here that the cell cycle-dependent expression of one of the G1-phase cyclins, cyclin D1, is dependent on the presence of a functional Rb protein. Rb-deficient tumor cell lines as well as cells expressing viral oncoproteins (large tumor antigen of simian virus 40, early region 1A of adenovirus, early region 7 of papillomavirus) have low or barely detectable levels of cyclin D1. Expression of cyclin D1, but not of cyclins A and E, is induced by transfection of the Rb gene into Rb-deficient tumor cells. Cotransfection of a reporter gene under the control of the D1 promoter, together with the Rb gene, into Rb-deficient cell lines demonstrates stimulation of the D1 promoter by Rb, which parallels the stimulation of endogenous cyclin D1 gene expression. Our finding that pRb stimulates expression of a key component of cell cycle control, cyclin D1, suggests the existence of a regulatory loop between pRb and cyclin D1 and extends existing models of tumor suppressor function.

• MeSH
• buněčný cyklus * MeSH
• cyklin D1 MeSH
• cykliny genetika   metabolismus   MeSH
• DNA primery chemie   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• molekulární sekvence - údaje MeSH
• nádorové buňky kultivované MeSH
• onkogenní proteiny genetika   metabolismus   MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese MeSH
• retinoblastomový protein * metabolismus   MeSH
• sekvence nukleotidů MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH

Cyclin D1 is a cell-cycle regulator essential for G1 phase progression and a candidate proto-oncogene implicated in pathogenesis of several human tumour types, including breast carcinomas. In spite of the accumulating genetic evidence, however, there are no data regarding abundance and properties of the cyclin D1 protein in breast cancer. We now report aberrant nuclear overexpression/accumulation of the cyclin D1 protein in about half of the 170 primary breast carcinoma specimens analyzed by monoclonal antibody immunohistochemistry, indicating that the frequency of cyclin D1 abnormalities may be considerably higher than previously deduced from DNA amplification studies. A comparison of the expression patterns in matched lesions at different stages of tumour progression revealed that the cyclin D1 protein aberration appears to reflect a relatively early event and that, when acquired by a tumour, it is maintained throughout breast cancer progression including metastatic spread. In both tumour tissues and breast cancer cell lines, the abundance of this protein shows characteristic variations consistent with a cell-cycle oscillation and the peak levels expressed in G1. In all 7 cell lines whose retinoblastoma (Rb) protein is mutant or complexed to SV40 T antigen, exceptionally low levels of cyclin D1 protein and mRNA were found. Antibody-mediated and anti-sense oligonucleotide knockout experiments demonstrate the requirement for the cell-cycle regulatory function of cyclin D1 in breast cancer lines with single or multiple copies of the gene and reveal the absence of such a requirement in the cell lines with Rb defects. Our data are consistent with the notion that the emerging "Rb-cyclin D1 pathway" represents a frequent target of oncogenic abnormalities in breast cancer.

• MeSH
• buněčný cyklus MeSH
• cyklin D1 MeSH
• cykliny analýza   fyziologie   MeSH
• geny retinoblastomu MeSH
• lidé MeSH
• messenger RNA analýza   MeSH
• molekulární sekvence - údaje MeSH
• nádory prsu * genetika   chemie   patologie   MeSH
• onkogenní proteiny analýza   fyziologie   MeSH
• prsy * chemie   patologie   MeSH
• RNA nádorová analýza   MeSH
• sekvence nukleotidů MeSH
• staging nádorů MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH

The retinoblastoma gene product (pRB) participates in the regulation of the cell division cycle through complex formation with numerous cellular regulatory proteins including the potentially oncogenic cyclin D1. Extending the current view of the emerging functional interplay between pRB and D-type cyclins, we now report that cyclin D1 expression is positively regulated by pRB. Cyclin D1 mRNA and protein is specifically downregulated in cells expressing SV40 large T antigen, adenovirus E1A, and papillomavirus E7/E6 oncogene products and this effect requires intact RB-binding, CR2 domain of E1A. Exceptionally low expression of cyclin D1 is also seen in genetically RB-deficient cell lines, in which ectopically expressed wild-type pRB results in specific induction of this G1 cyclin. At the functional level, antibody-mediated cyclin D1 knockout experiments demonstrate that the cyclin D1 protein, normally required for G1 progression, is dispensable for passage through the cell cycle in cell lines whose pRB is inactivated through complex formation with T antigen, E1A, or E7 oncoproteins as well as in cells which have suffered loss-of-function mutations of the RB gene. The requirement for cyclin D1 function is not regained upon experimental elevation of cyclin D1 expression in cells with mutant RB, while reintroduction of wild-type RB into RB-deficient cells leads to restoration of the cyclin D1 checkpoint. These results strongly suggest that pRB serves as a major target of cyclin D1 whose cell cycle regulatory function becomes dispensable in cells lacking functional RB. Based on available data including this study, we propose a model for an autoregulatory feedback loop mechanism that regulates both the expression of the cyclin D1 gene and the activity of pRB, thereby contributing to a G1 phase checkpoint control in cycling mammalian cells.

• MeSH
• adenovirové proteiny E1A * fyziologie   MeSH
• antigeny transformující polyomavirové * fyziologie   MeSH
• buněčné linie MeSH
• buněčný cyklus * MeSH
• cyklin D1 MeSH
• cykliny fyziologie   metabolismus   MeSH
• lidé MeSH
• lidské adenoviry genetika   MeSH
• onkogenní proteiny virové * fyziologie   MeSH
• onkogenní proteiny * fyziologie   MeSH
• onkogeny * MeSH
• opičí virus SV40 genetika   MeSH
• Papillomaviridae genetika   MeSH
• regulace exprese virových genů MeSH
• retinoblastomový protein * fyziologie   MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH