Cyclin D1/PRAD1/BCL-1 alternative transcript [B] protein product in B-lymphoid malignancies with t(11;14)(q13;q32) translocation

D-Type Cyclins in Development and Disease

D-type cyclins encode G1/S cell cycle checkpoint proteins, which play a crucial role in defining cell cycle exit and progression. Precise control of cell cycle exit is vital during embryonic development, with defects in the pathways regulating intracellular D-type cyclins resulting in abnormal initiation of stem cell differentiation in a variety of different organ systems. Furthermore, stabilisation of D-type cyclins is observed in a wide range of disorders characterized by cellular over-proliferation, including cancers and overgrowth disorders. In this review, we will summarize and compare the roles played by each D-type cyclin during development and provide examples of how their intracellular dysregulation can be an underlying cause of disease.

Influence of cyclin D1 splicing variants expression on breast cancer chemoresistance via CDK4/CyclinD1-pRB-E2F1 pathway

Cyclin D1 (CCND1), a mediator of cell cycle control, has a G870A polymorphism which results in the formation of two splicing variants: full-length CCND1 (CCND1a) and C-terminally truncated CCND1 species (CCND1b). However, the role of CCND1a and CCND1b variants in cancer chemoresistance remains unknown. Therefore, this study aimed to explore the molecular mechanism of alternative splicing of CCND1 in breast cancer (BC) chemoresistance. To address the contribution of G870A polymorphism to the production of CCND1 variants in BC chemoresistance, we sequenced the G870A polymorphism and analysed the expressions of CCND1a and CCND1b in MCF-7 and MCF-7/ADM cells. In comparison with MCF-7 cells, MCF-7/ADM cells with the A allele could enhance alternative splicing with the increase of SC-35, upregulate the ratio of CCND1b/a at both mRNA and protein levels, and activate the CDK4/CyclinD1-pRB-E2F1 pathway. Furthermore, CCND1b expression and the downstream signalling pathway were analysed through Western blotting and cell cycle in MCF-7/ADM cells with knockdown of CCND1b. Knockdown of CCND1b downregulated the ratio of CCND1b/a, demoted cell proliferation, decelerated cell cycle progression, inhibited the CDK4/CyclinD1-pRB-E2F1 pathway and thereby decreased the chemoresistance of MCF-7/ADM cells. Finally, CCND1 G870A polymorphism, the alternative splicing of CCDN1 was detected through Sequenom Mass ARRAY platform, Sanger sequencing, semi-quantitative RT-PCR, Western blotting and immunohistochemistry in clinical BC specimens. The increase of the ratio of CCND1b/a caused by G870A polymorphism was involved in BC chemoresistance. Thus, these findings revealed that CCND1b/a ratio caused by the polymorphism is involved in BC chemoresistance via CDK4/CyclinD1-pRB-E2F1 pathway.

Association between cyclin D1 (CCND1) G870A polymorphism and gastric cancer risk: a meta-analysis

Published data on the association between cyclin D1 (CCND1) G870A polymorphism and gastric cancer (GC) risk are inconclusive. Thus, we conducted a meta-analysis to evaluate the relationship between CCND1 G870A polymorphism and GC risk. We searched PubMed, EMBASE, Web of science and the Cochrane Library up to June 12, 2015 for relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. Nine studies published from 2003 to 2014, with a total of 1813 cases and 2173 controls, were included in this meta-analysis. The pooled results showed that there was no association between CCND1 G870A polymorphism and GC risk in any genetic model. The subgroup analysis stratified by ethnicity showed an increased breast cancer risk in Caucasian based on heterozygote comparison (GA vs. GG: OR=1.49, 95% CI=1.06-2.10, P=0.02). We found the same association in population based (PB) stratified analyses by Source of controls (AA vs. GG: OR=1.39, 95% CI=1.01-1.93, 0.05). When stratifying by the type, Sex and H. pylori infection in dominant model, Interestingly, we found the opposite result in Male (AA + GA vs. GG: OR=0.5, 95% CI=0.33-0.76, P=0.001), there were no association between CCND1 G870A polymorphism and GC risk in any other subgroup. This meta-analysis suggests that CCND1 G870A polymorphism is a risk factor for susceptibility to GC in Caucasians and in general populations. While, CCND1 G870A polymorphism plays a possible protective effect in GC in Male. Further large scale multicenter epidemiological studies are warranted to confirm this finding.

The Fbx4 tumor suppressor regulates cyclin D1 accumulation and prevents neoplastic transformation

Skp1-Cul1-F-box (SCF) E3 ubiquitin ligase complexes modulate the accumulation of key cell cycle regulatory proteins. Following the G(1)/S transition, SCF(Fbx4) targets cyclin D1 for proteasomal degradation, a critical event necessary for DNA replication fidelity. Deregulated cyclin D1 drives tumorigenesis, and inactivating mutations in Fbx4 have been identified in human cancer, suggesting that Fbx4 may function as a tumor suppressor. Fbx4(+/-) and Fbx4(-/-) mice succumb to multiple tumor phenotypes, including lymphomas, histiocytic sarcomas and, less frequently, mammary and hepatocellular carcinomas. Tumors and premalignant tissue from Fbx4(+/-) and Fbx4(-/-) mice exhibit elevated cyclin D1, an observation consistent with cyclin D1 as a target of Fbx4. Molecular dissection of the Fbx4 regulatory network in murine embryonic fibroblasts (MEFs) revealed that loss of Fbx4 results in cyclin D1 stabilization and nuclear accumulation throughout cell division. Increased proliferation in early passage primary MEFs is antagonized by DNA damage checkpoint activation, consistent with nuclear cyclin D1-driven genomic instability. Furthermore, Fbx4(-/-) MEFs exhibited increased susceptibility to Ras-dependent transformation in vitro, analogous to tumorigenesis observed in mice. Collectively, these data reveal a requisite role for the SCF(Fbx4) E3 ubiquitin ligase in regulating cyclin D1 accumulation, consistent with tumor suppressive function in vivo.

Nuclear cyclin D1/CDK4 kinase regulates CUL4 expression and triggers neoplastic growth via activation of the PRMT5 methyltransferase

Cyclin D1 elicits transcriptional effects through inactivation of the retinoblastoma protein and direct association with transcriptional regulators. The current work reveals a molecular relationship between cyclin D1/CDK4 kinase and protein arginine methyltransferase 5 (PRMT5), an enzyme associated with histone methylation and transcriptional repression. Primary tumors of a mouse lymphoma model exhibit increased PRMT5 methyltransferase activity and histone arginine methylation. Analyses demonstrate that MEP50, a PRMT5 coregulatory factor, is a CDK4 substrate, and phosphorylation increases PRMT5/MEP50 activity. Increased PRMT5 activity mediates key events associated with cyclin D1-dependent neoplastic growth, including CUL4 repression, CDT1 overexpression, and DNA rereplication. Importantly, human cancers harboring mutations in Fbx4, the cyclin D1 E3 ligase, exhibit nuclear cyclin D1 accumulation and increased PRMT5 activity.

Cyclin D1b is aberrantly regulated in response to therapeutic challenge and promotes resistance to estrogen antagonists

Cyclin D1 is a key mediator of cell cycle progression that is aberrantly regulated in multiple cancers, especially in breast cancers. A number of studies have indicated that a polymorphism in a splice donor site in the cyclin D1 gene is associated with alternative splicing and the production of the alternative cyclin D1b transcript. Furthermore, this polymorphism is selectively associated with disease outcomes. However, relatively little is known regarding the protein product of the alternatively spliced message, cyclin D1b. Using antibodies specific for cyclin D1b, it was found that this protein is readily detectable in a number of cancer cell lines and primary breast cancers. Whereas cyclin D1b interacts with cyclin-dependent kinase 4 (CDK4), it is relatively inefficient at mediating RB phosphorylation and cell cycle progression in model systems due to the lack of exon 5 of cyclin D1-encoded sequences. However, cyclin D1b protein levels are not significantly attenuated by DNA damage or antiestrogen treatment, indicating that the protein may have significant effect on the response to such therapeutic modalities. Whereas enforced expression of cyclin D1b was not sufficient to abrogate DNA damage checkpoint responses, it did efficiently overcome cell cycle arrest mediated by antiestrogen therapeutics. This action of cyclin D1b was not associated with effects on estrogen receptor activity, but was rather dependent on functional association with CDK4. Combined, these studies indicate that the cyclin D1b protein is aberrantly regulated and could contribute to therapeutic failure in the context of ER-positive breast cancer.

Alteration of cyclin D1 transcript elongation by a mutated transcription factor up-regulates the oncogenic D1b splice isoform in cancer

Pre-mRNA splicing and polyadenylation are tightly connected to transcription, and transcriptional stimuli and elongation dynamics can affect mRNA maturation. However, whether this regulatory mechanism has a physio/pathological impact is not known. In cancer, where splice variant expression is often deregulated, many mutated oncogenes are transcriptional regulators. In particular, the Ewing sarcoma (EwSa) oncogene, resulting from a fusion of the EWS and FLI1 genes, encodes a well characterized transcription factor. EWS-FLI1 directly stimulates transcription of the CCND1 protooncogene encoding cyclin D1a and a less abundant but more oncogenic splice isoform, D1b. We show that, although both EWS and EWS-FLI1 enhance cyclin D1 gene expression, they regulate the D1b/D1a transcript ratio in an opposite manner. Detailed analyses of RNA polymerase dynamics along the gene and of the effects of an inhibitor of elongation show that EWS-FLI1 favors D1b isoform expression by decreasing the elongation rate, whereas EWS has opposite effects. As a result, the D1b/D1a ratio is elevated in EwSa cell lines and tumors. The endogenous D1b protein is enriched in nuclei, where the oncogenic activity of cyclin D1 is known to occur, and depleting D1b in addition to D1a results in a stronger reduction of EwSa cell growth than depleting D1a only. These data show that elevated expression of a splice isoform in cancer can be due to an alteration of the transcription process by a mutated transcriptional regulator and provide evidence for a physio/pathological impact of the coupling between transcription and mRNA maturation.

Silencing Bcl-2 in models of mantle cell lymphoma is associated with decreases in cyclin D1, nuclear factor-kappaB, p53, bax, and p27 levels

Molecular mechanisms responsible for lymphoma resistance to apoptosis often involve the bcl-2 pathway. In this study, we investigated the cell signaling pathways activated in bcl-2-overexpressing human mantle cell lymphoma cell lines (JVM-2 and Z-138) that have been treated with oblimersen, a molecular gene silencing strategy that effectively suppresses bcl-2 in vitro and in vivo. Z-138 cells expressed higher levels of bcl-2 and were more sensitive to the effects of bcl-2 silencing, mediated by oblimersen or bcl-2 small interfering RNA, in vitro. Tumors derived following injection of Z-138 cells were sensitive to oblimersen as judged by decreases in tumor growth rate and decreases in cell proliferation (as measured by Ki-67). Immunohistochemistry and Western blot analysis of oblimersen-treated Z-138 tumors revealed a dose-dependent decrease in bcl-2 levels and an associated increase in the proapoptotic proteins caspase-3 and caspase-9. Silencing bcl-2 in Z-138 xenografts revealed an associated dose-dependent suppression of bax, a decrease in nuclear factor-kappaB and phospho-nuclear factor-kappaB, and transient loss of p53 levels. Coimmunoprecipitation studies suggest that the latter observation is mediated by an association between bcl-2 and phospho-mdm2. Bcl-2 silencing also led to p27 down-regulation and coimmunoprecipitation studies point to a role for bcl-2 in regulation of p27 localization/degradation. Bcl-2 silencing was also correlated with loss of cyclin D1a protein levels but not cyclin D1b levels. Coimmunoprecipitation studies indicate that bcl-2 may mediate its effects on cyclin D1a via interaction with p38 mitogen-activated protein kinase as well as a previously unreported interaction between bcl-2 and cyclin D1a.

Nuclear accumulation of cyclin D1 during S phase inhibits Cul4-dependent Cdt1 proteolysis and triggers p53-dependent DNA rereplication

Deregulation of cyclin D1 occurs in numerous human cancers through mutations, alternative splicing, and gene amplification. Although cancer-derived cyclin D1 mutants are potent oncogenes in vitro and in vivo, the mechanisms whereby they contribute to neoplasia are poorly understood. We now provide evidence derived from both mouse models and human cancer-derived cells revealing that nuclear accumulation of catalytically active mutant cyclin D1/CDK4 complexes triggers DNA rereplication, resulting from Cdt1 stabilization, which in turn triggers the DNA damage checkpoint and p53-dependent apoptosis. Loss of p53 through mutations or targeted deletion results in increased genomic instability and neoplastic growth. Collectively, the data presented reveal mechanistic insights into how uncoupling of critical cell cycle regulatory events will perturb DNA replication fidelity, thereby contributing to neoplastic transformation.

mRNA stability and cancer: an emerging link?

Many oncogenes, growth factor, cytokine and cell-cycle genes are regulated post-transcriptionally. The major mechanism is by controlling the rate of mRNA turnover for transcripts bearing destabilizing cis-elements. To date, only a handful of regulatory factors have been identified that appear to control a large pool of target mRNAs, suggesting that a slight perturbation in the control mechanism may generate wide-ranging effects that could contribute to the development of a complex disorder such as cancer. In support of this view, mRNA turnover responds to signalling pathways that are often overactive in cancer, suggesting a post-transcriptional component in addition to the well-recognised transcriptional aspect of oncogenesis. Here the authors review examples of deregulated post-transcriptional control in oncogenesis, discuss post-transcriptionally regulated transcripts of oncologic significance, and consider the key role of signalling pathways in linking both processes and as an enticing therapeutic prospect.

Genetic and molecular pathogenesis of mantle cell lymphoma: perspectives for new targeted therapeutics

Mantle cell lymphoma (MCL) is a well-defined lymphoid malignancy characterized by a rapid clinical evolution and poor response to current therapeutic protocols. The genetic and molecular mechanisms involved in its pathogenesis combine the dysregulation of cell proliferation and survival pathways with a high level of chromosome instability that seems related to the disruption of the DNA damage response pathway. Understanding these mechanisms and how they affect tumour behaviour is providing the rationale for the identification of reliable predictors of clinical evolution and the design of innovative therapeutic strategies that could open new avenues for the treatment of patients with MCL.

Alternative cyclin D1 forms a and b have different biological functions in the cell cycle of B lymphocytes

Cyclin D1 is an important regulator of the early phase of the cell cycle and the transcriptional machinery. It is often deregulated in human tumors of various origins and is considered to be an oncogene. The CCND1 gene encoding cyclin D1 generates two mRNAs by alternative splicing, leading to the production of two alternative proteins: a long form a (36 kDa) and a short form b (30-31 kDa) from which the C-terminal moiety required for protein stability and sub-cellular localization has been deleted. Both forms of RNA and protein have been detected in B-cell hemopathies, but their respective roles are unclear. We investigated the function of cyclin D1b in cell cycle regulation, by generating B-cell lines displaying conditional expression of isoform b. Comparisons of these cell lines (BD1b series) with previously obtained cell lines expressing cyclin D1a demonstrated that cyclin D1b had no cell cycle regulatory properties.

The cyclin D1b splice variant: an old oncogene learns new tricks

The function of cyclin D1 as a positive regulator of the cell cycle and proto-oncogene has been well established. Cyclin D1 elicits its pro-proliferative function early in G1 phase, through its ability to activate cyclin dependent kinase (CDK) 4 or 6. Active CDK4/6-cyclin D1 complexes phosphorylate substrates that are critical for modulating G1 to S phase progression, and in this manner promote cellular proliferation. Emerging data from a number of model systems revealed that cyclin D1 also holds multiple, kinase-independent cellular functions. First, cyclin D1 assists in sequestering CDK inhibitors (e.g. p27^kip1), thus bolstering late G1 CDK activity. Second, cyclin D1 is known to bind and modulate the action of several transcription factors that hold significance in human cancers. Thus, cyclin D1 impinges on several distinct pathways that govern cancer cell proliferation. Although intragenic somatic mutation of cyclin D1 in human disease is rare, cyclin D1 gene translocation, amplification and/or overexpression are frequent events in selected tumor types. Additionally, a polymorphism in the cyclin D1 locus that may affect splicing has been implicated in increased cancer risk or poor outcome. Recent functional analyses of an established cyclin D1 splice variant, cyclin D1b, revealed that the cyclin D1b isoform harbors unique activities in cancer cells. Here, we review the literature implicating cyclin D1b as a mediator of aberrant cellular proliferation in cancer. The differential roles of cyclin D1 and the cyclin D1b splice variant in prostate cancer will be also be addressed, wherein divergent functions have been linked to altered proliferative control.

Cyclin D1: polymorphism, aberrant splicing and cancer risk

The cyclin D1 proto-oncogene exercises powerful control over the mechanisms that regulate the mitotic cell cycle, and excessive cyclin D1 expression and/or activity is common in human cancers. Although somatic mutations of the cyclin D1 locus are rarely observed, mounting evidence demonstrates that a specific polymorphism of cyclin D1 (G/A870) and a protein product of a potentially related alternate splicing event (cyclin D1b) may influence cancer risk and outcome. Herein, we review the epidemiological and functional literatures that link these alterations of cyclin D1 to human tumor development and progression.

Expression of constitutively nuclear cyclin D1 in murine lymphocytes induces B-cell lymphoma

Mantle cell lymphoma (MCL) is a B-cell lymphoma characterized by overexpression of cyclin D1 due to the t(11;14) chromosomal translocation. While expression of cyclin D1 correlates with MCL development, expression of wild-type (WT) cyclin D1 transgene in murine lymphocytes is unable to drive B-cell lymphoma. As cyclin D1 mutants that are refractory to nuclear export display heighten oncogenicity in vitro compared with WT D1, we generated mice expressing FLAG-D1/T286A, a constitutively nuclear mutant, under the control of the immunoglobulin enhancer, Emu. D1/T286A transgenic mice universally develop a mature B-cell lymphoma. Expression of D1/T286A in B lymphocytes results in S phase entry in resting lymphocytes and increased apoptosis in spleens of young premalignant mice. Lymphoma onset correlates with perturbations in p53/MDM2/p19Arf expression and with BcL-2 overexpression suggesting that alterations in one or both of these pathways may contribute to lymphoma development. Our results describe a cyclin D1-driven model of B-cell lymphomagenesis and provide evidence that nuclear-retention of cyclin D1 is oncogenic in vivo.

Cyclin D1 in Breast Cancer Pathogenesis

Taking a perspective on available evidence that emphasizes relevance to human disease, cyclin D1 is solidly established as an oncogene with an important pathogenetic role in breast cancer and other human tumors. However, the precise cellular mechanisms through which aberrant cyclin D1 expression drives human neoplasia are less well established. Indeed, emerging evidence suggests that cyclin D1 might act, predominantly or at least in part, through pathways that do not involve its widely accepted function as a cell cycle regulator. Although therapeutic exploitation of the role of cyclin D1 as a molecular driver of breast cancer carries great promise, it is also suggested that direct targeting of the cyclin D1 gene or gene products may prove more successful than approaches that rely on arguably incomplete knowledge of the oncogenic mechanisms of cyclin D1.

Inhibition of IκB Kinase Activity by Acetyl-boswellic Acids Promotes Apoptosis in Androgen-independent PC-3 Prostate Cancer Cells in Vitro and in Vivo

Signaling through NF-kappaB has been implicated in the malignant phenotype as well as the chemoresistance of various cancers. Here we show that the natural compounds acetyl-beta-boswellic acid and acetyl-11-keto-beta-boswellic acid (AKbetaBA) inhibit proliferation and elicit cell death in chemoresistant androgen-independent PC-3 prostate cancer cells in vitro and in vivo. Induction of apoptosis was demonstrated in cultured PC-3 cells by several parameters including mitochondrial cytochrome c release and DNA fragmentation. At the molecular level these compounds inhibit constitutively activated NF-kappaB signaling by intercepting the IkappaB kinase (IKK) activity; signaling through the interferon-stimulated response element remained unaffected, suggesting specificity for IKK inhibition. The impaired phosphorylation of p65 and the reduced nuclear translocation of NF-kappaB proteins were associated with down-regulation of the constitutively overexpressed and NF-kappaB-dependent antiapoptotic proteins Bcl-2 and Bcl-x(L). In addition, expression of cyclin D1, a crucial cell cycle regulator, was reduced as well. Down-regulation of IKK by antisense oligodeoxynucleotides confirmed the essential role of IKK inhibition for the proliferation of the PC-3 cells. Both compounds tested were active in vivo, yet AKbetaBA proved to be far superior. Indeed, topical application of water-soluble AKbetaBA-gamma-cyclodextrin on PC-3 tumors xenografted onto chick chorioallantoic membranes induced concentration-dependent inhibition of proliferation as well as apoptosis. Similarly, in nude mice carrying PC-3 tumors, systemic application of AKbetaBA-gamma-cyclodextrin inhibited tumor growth and triggered apoptosis in the absence of detectable systemic toxicity. Thus, AKbetaBA and related compounds acting on IKK might provide a novel approach for the treatment of chemoresistant human tumors such as androgen-independent human prostate cancers.

Induced expression of humanCCND1 alternative transcripts in mouseCyl-1 knockout fibroblasts highlights functional differences

Splicing of human cyclin D1 (CCND1) mRNA producing transcripts a and b is modulated by a common polymorphism (A --> G) located in a conserved splice donor region at nucleotide 870. CCND1 A/G(870) genotype is associated with tumour progression and clinical outcome in a variety of cancers. Although in vitro expression of cyclin D1 transcript a (CCND1(tra)) has been widely investigated, few studies have examined the expression of CCND1 transcript b (CCND1(trb)). We have studied the effects of inducible expression of human CCND1(trb) in comparison with human CCND1(tra) in a mouse fibroblast knock-out for cyclin D1 (MEF(Cyl-1-/-)). Inducible expression was in stable clones isolated from MEF(Cyl-1-/-) transfectants. Induction of CCND1(tra) produced a 36-kDa protein, which led to a significant increase in the proportion of cells in S-phase, as detected by BrdU incorporation after 32 hr, compared to non-induced cells (p = 0.012). Clones induced to express CCND1(tra) exhibited a significantly increased ability to grow in serum depleted (2% FCS) medium compared to non-induced clones (p = 0.0004). Induced expression of CCND1(trb) in MEF(Cyl-1-/-) transfectants produced a 31-kDa protein and resulted in no significant difference in DNA synthesis, neither did the cells acquire the ability to grow in serum-depleted conditions compared to non-induced cells. Induction of CCND1(trb) significantly enhanced the ability of MEF(Cyl-1-/-) transfectants to form colonies in soft agar, (average 30-fold increase) compared to non-induced clones or those induced to express CCND1(tra). Our data supports the emerging view that CCND1 alternate transcripts encode proteins with differing independent biological functions. We suggest that CCND1(tra) encodes a protein involved in regulating mitogen responsive, anchorage-dependent G(1) progression, whereas CCND1(trb) modulates the ability of the cell to grow in an anchorage-independent manner.

Cyclin D1 polymorphism and expression in patients with squamous cell carcinoma of the head and neck

We have previously reported that the cyclin D1 (CCND1) GG870 genotype was associated with poorly differentiated tumors and reduced disease-free interval in patients with squamous cell carcinoma of the head and neck (SCCHN). We have now examined the association of this and a second CCND1 polymorphism with gene expression and outcome in SCCHN patients. Analysis of a CCND1 G/C1722 polymorphism revealed that CCND1 CC1722 genotype was associated with poorly differentiated tumors [P = 0.005; odds ratio (OR), 5.7; 95% CI, 1.7 to 19.2), and reduced disease-free interval (P = 0.003; Hazard Ratio (HR), 7.3; 95% CI, 1.1 to 27.2.) independently from the influence of CCND1 GG870 genotype. Patients whose tumors were negative for cyclin D1 were associated with reduced disease-free interval (P = 0.028; HR, 4.1; 95% CI, 1.4 to 14.2). Although G/C1722 genotypes were not associated with expression, we found a significant trend between reduced expression of cyclin D1 in patients with the CCND1 GG870 genotype (P = 0.04). Splicing of CCND1 mRNA in head and neck tissues was modulated by CCND1 A/G870 alleles, thus CCND1 transcript a was spliced equally from CCND1 A870 and G870 alleles, whereas CCND1 transcript b was spliced mainly from the CCND1 A870 allele. Our analysis has also identified differences in cyclin D1 genotype and protein expression and the pathogenesis of SCCHN in males and females. Thus, CCND1 CC1722 genotype was more common in female patients (P = 0.019; OR, 3.3; 95% CI, 1.3 to 10) and cyclin D1 expression was more frequent (chi-square1, 3.96; P = 0.046) and at higher levels (P = 0.004) in tumors from female patients. In summary, our data show that the two CCND1 polymorphic sites are independently associated with tumor biology and clinical outcome. CCND1 A/G870 alleles affect gene expression in head and neck tissues. We also provide preliminary evidence that the molecular genetics of SCCHN development may be influenced by patient gender.