| 1. |
- Chen, Dan, et al.
(författare)
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Analysis of the genetic architecture of susceptibility to cervical cancer indicates that common SNPs explain a large proportion of the heritability
- 2015
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 36:9, s. 992-998
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Tidskriftsartikel (refereegranskat)abstract
- The genetic architecture of susceptibility to cervical cancer is not well-understood. By using a genome-wide association study (GWAS) of 1034 cervical cancer patients and 3948 controls with 632 668 single-nucleotide polymorphisms (SNPs), we estimated that 24.0% [standard error (SE) = 5.9%, P = 3.19 x 10(-6)] of variation in liability to cervical cancer is captured by autosomal SNPs, a bit lower than the heritability estimated from family study (27.0%), suggesting that a substantial proportion of the heritability is tagged by common SNPs. The remaining missing heritability most probably reflects incomplete linkage disequilibrium between causal variants and the genotyped SNPs. The variance explained by each chromosome is not related to its length (R-2 = 0.020, P = 0.516). Published genome-wide significant variants only explain 2.1% (SE = 1.5%, P = 0) of phenotypic variance, which reveals that most of the heritability has not been detected, presumably due to small individual effects. Another 2.1% (SE = 1.1%, P = 0.013) of variation is attributable to biological pathways associated with risk of cervical cancer, supporting that pathway analysis can identify part of the hidden heritability. Except for human leukocyte antigen genes and MHC class I polypeptide-related sequence A (MICA), none of the 82 candidate genes/regions reported in other association studies contributes to the heritability of cervical cancer in our dataset. This study shows that risk of cervical cancer is influenced by many common germline genetic variants of small effects. The findings are important for further study design to identify the hiding heritability that has not yet been revealed. More susceptibility loci are yet to be found in GWASs with higher power.
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| 2. |
- Chen, Dan, et al.
(författare)
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MICA polymorphism : biology and importance in cancer
- 2014
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 35:12, s. 2633-2642
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Forskningsöversikt (refereegranskat)abstract
- The major histocompatibility complex class I polypeptide-related sequence A gene (MICA) encodes a membrane-bound protein acting as a ligand to stimulate an activating receptor, NKG2D, expressed on the surface of essentially all human natural killer (NK), γδ T and CD8(+) αβ T cells. MICA protein is absent from most cells but can be induced by infections and oncogenic transformation and is frequently expressed in epithelial tumors. Upon binding to MICA, NKG2D activates cytolytic responses of NK and γδ T cells against infected and tumor cells expressing MICA. Therefore, membrane-bound MICA acts as a signal during the early immune response against infection or spontaneously arising tumors. On the other hand, human tumor cells spontaneously release a soluble form of MICA, causing the downregulation of NKG2D and in turn severe impairment of the antitumor immune response of NK and CD8(+) T cells. This is considered to promote tumor immune evasion and also to compromise host resistance to infections. MICA is the most polymorphic non-classical class I gene. A possible association of MICA polymorphism with genetic predisposition to different cancer types has been investigated in candidate gene-based studies. Two genome-wide association studies have identified loci in MICA that influence susceptibility to cervical neoplasia and hepatitis C virus-induced hepatocellular carcinoma, respectively. Given the current level of interest in the field of MICA gene, we discuss the genetics and biology of the MICA gene and the role of its polymorphism in cancer. Gaps in our understanding and future research needs are also discussed.
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| 3. |
- Chen, Dan, et al.
(författare)
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Systematic investigation of contribution of genetic variation in the HLA-DP region to cervical cancer susceptibility
- 2014
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 35:8, s. 1765-1769
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Tidskriftsartikel (refereegranskat)abstract
- Compared with the other human leukocyte antigen (HLA) genes, few studies have evaluated the role of HLA-DP genes in cervical cancer pathogenesis. A recent genome-wide association study (GWAS) in the Swedish population has identified a susceptibility locus for cervical cancer within the HLA-DP region. To further study this locus, we imputed classic HLA alleles using single-nucleotide polymorphism (SNP) data and analysed 449 genotyped and 3066 imputed SNPs in 1034 cervical cancer patients and 3948 controls. We confirmed that the strongest signal came from a SNP located at HLA-DPB2 [rs3117027, odds ratio (OR) = 1.29, 95% confidence interval (CI) = 1.16-1.43, P = 1.9 x 10(-6) for A allele] and that this effect is not driven by associations with classic HLA alleles. In silico analysis further revealed that this SNP is highly correlated with rs3129294 (D' = 1, r(2) = 0.95 in controls), which may have a putative regulatory function. We also identified an independent association at DPB1*0402, which conferred decreased risk of cervical cancer (OR = 0.75, 95% CI = 0.63-0.89, P = 7.0 x 10(-4)) and is independent of previously described associations with HLA-B*0702, DRB1*1501-DQB1*0602, and DRB1*1301-DQA1*0103-DQB1*0603. No association was found with the two SNPs (rs4282438 or rs9277952) that were recently identified within the HLA-DP region in a cervical cancer GWAS in the Chinese population. Our study provides the first systematic investigation of the association of genetic variants in the HLA-DP region with cervical cancer susceptibility and provides further insight into the contribution of polymorphisms in the HLA-DP region to risk of cervical cancer.
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| 4. |
- Cui, Tao, 1982-, et al.
(författare)
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Invasive cervical tumors with high and low HPV titer represent molecular subgroups with different disease etiology
- 2019
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 40:2, s. 269-278
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Tidskriftsartikel (refereegranskat)abstract
- Invasive cervical cancer (ICC) with very low titer of high-risk human papillomavirus (HPV) has worse clinical outcome than cases with high titer, indicating a difference in molecular etiology. Fresh-frozen ICC tumors (n = 49) were classified into high- and low-HPV-titer cases using real-time PCR-based HPV genotyping. The mutation spectra were studied using the AmpliSeq Comprehensive Cancer Panel and the expression profiles using total RNA sequencing, and the results were validated using the AmpliSeq Transcriptome assay. HPV DNA genotyping and RNA sequencing showed that 16.6% of ICC tumors contained very low levels of HPV DNA and HPV transcripts. Tumors with low HPV levels had more mutations with a high allele frequency and fewer mutations with low allele frequency relative to tumors with high HPV titer. A number of genes showed significant expression differences between HPV titer groups, including genes with somatic mutations. Gene ontology and pathway analyses implicated the enrichment of genes involved in DNA replication, cell cycle control and extracellular matrix in tumors with low HPV titer. The results indicate that in low titer tumors, HPVs act as trigger of cancer development whereas somatic mutations are clonally selected and become drivers of the tumor development process. In contrast, in tumors with high HPV titer the expression of HPV oncoproteins plays a major role in tumor development and the many low frequency somatic mutations represent passengers. This putative subdivision of invasive cervical tumors may explain the higher radiosensitivity of ICC tumors with high HPV titer and thereby have consequences for clinical management.
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| 5. |
- Johanneson, Bo, et al.
(författare)
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Systematic validation of hypothesis-driven candidate genes for cervical cancer in a genome-wide association study
- 2014
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 35:9, s. 2084-2088
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Tidskriftsartikel (refereegranskat)abstract
- A large number of genetic associations with cervical cancer have been reported in hypothesis-driven candidate gene studies, but most studies have not included an independent replication or the results have been inconsistent between studies. In order to independently validate these associations, we re-examined 58 candidate gene/regions previously reported to be associated with cervical cancer using the gene-based Adaptive Rank Truncated Product (ARTP) test in a genome-wide association study of 1,034 cervical cancer patients and 3,948 controls from the Swedish population. Of the 58 gene/regions, 8 had a nominal p-value < 0.05 (Tumor necrosis factor [TNF], p = 5.0×10(-4); DEAD (Asp-Glu-Ala-Asp) box helicase 1 [DDX1], p = 2.2×10(-3); Exonuclease 1 [EXO1], p=4.7×10(-3); Excision repair cross-complementing rodent repair deficiency, complementation group 1 [ERCC1], p = 0.020; Transmembrane channel-like 6 and 8 genes [TMC6-TMC8], p = 0.023; Secreted phosphoprotein 1 [SPP1], p= 0.028; v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 [ERBB2], p = 0.033 and Chloride channel, voltage-sensitive 7 [CLCN7], p = 0.047). After correction for multiple testing only TNF remained statistically significant (p = 0.028). Two single-nucleotide polymorphisms that are in nearly perfect linkage disequilibrium (LD) (rs2857602 and rs2844484) contributed most to the association with TNF. However, they are not independent from the previously reported associations within the MHC region. The very low number of previously reported associations with cervical cancer that replicate in the Swedish population underscore the need to apply more stringent criteria when reporting associations, including the prerequisite of replicating the association as part of the original study.
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