Genetic Associations Between Candidate Gene Polymorphisms And Susceptibility To Hepatocellular Carcinoma, Nasopharyngeal Carcinoma And Sepsis

ChapterⅠ: Background and Objective: Hepatocellular carcinoma (HCC) and nasopharyngeal carcinoma (NPC) are the prevalent malignancies in China, and develop through multiple stages by interactions between environmental and genetic factors. At present, the difficulty of early diagnosis, high rate of recurrence and metastasis and poor prognosis are the major problems in the treatment of the two cancers. Hence, the research on the pathogenesis of these cancers is of great importance. Malignant growth and metastasis are key features and also predictors for poor prognosis, and during this progress, heparanase (HPA) as a mammalian endo-β-D-glycosidase, play a key role. HPA can specifically cleave heparan sulfate (HS) molecules that are the side chains of HSPGs which are one of the main components of the extracellular matrix (ECM) so that tumor cells can break through the barrier of ECM. Clinical pathological studies have shown that HPA is up-regulated in HCC tissues and correlates with patient survival. Besides, animal model studies suggested that excessive heparanase overexpression can accelerated heparan sulfate proteoglycans (HSPG) turnover, the release of HS-related sequestered growth factors and tumor angiogenesis and metastasis. A large number of genetic association studies suggest that host genetic factors determine interindividual differences in tumor susceptibility. Thus, polymorphisms in heparanase gene (HPSE) would influence susceptibility to HCC and NPC. Then in present study we systematically assessed the association between polymorphisms in HPSE and susceptibility to HCC and NPC. Methods: 434 HCC patients, 855 NPC patients and 1036 controls were recruited at the Guangxi Cancer Hospital (Nanning, China) and the surrounding regions, southern China. Then 6 htSNPs (haplotype-tagging SNP, htSNP) in HPSE were genotyped by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism, PCR-RFLP) and SNPstream methods in the HCC and NPC case-control populations. Use unconditional logistic regression analyses to assess association between polymorphisms and susceptibility to HCC and NPC controlling for confounding factors. Results: A significant correlation was found between the HPSE polymorphism rs12331678 in non-HBV carriers (adjusted OR, 2.19; 95% CI, 1.25-3.85; P = 0.0074) adjusted by sex, age, status of smoking and drinking, pack-years of smoking. When compared with the statistical significance level required after correction for multiple testing (SNPSpD), the associations remained significant. Furthermore, when the analyses were stratified by sex, age, status of smoking and drinking, pack-years of smoking, there was no significant association between rs12331678 and HCC risk. However, no association of polymorphisms in HPSE with NPC risk or severity was suggested. Conclusion: Through the study of genetic association between HPSE polymorphisms and susceptibility to HCC and NPC, HPSE could be a predisposing gene of HCC. Our findings may help to clarify the pathogenesis and improve the prevention of HCC.ChapterⅡ: Background and Objective: Critical illness after severe infection, as manifested by patients with sepsis, is characterized by severe inflammation and the unexpected and inappropriate inflammatory response to an infectious process can result in severe sepsis, septic shock, multiple organ dysfunction syndrome (MODS), death or risk for secondary infection. Cytoplasmic PRRs (pattern recognition receptor, PRR) exist to detect invasive intracellular pathogens The NLRs (NOD-like receptor) proteins recognize common fragments of bacterial peptidoglycan and active inflammatory caspases (including CASP1, CASP4, CASP5, CASP12, clustering on chromosome 11q22.3) that play a core role in the maturation of pro-inflammatory cytokines. A number of studies suggest that host predisposition influences risk of and outcome during sepsis. Genetic polymorphisms represent interindividual genetic variability and may help to explain host predisposition. Polymorphisms affecting inflammatory caspase-related responses could predispose to excessive inflammation or hyporesponsiveness during an infection and contribute to an increased risk for poor outcomes in patients with sepsis. We indentify polymorphisms causing abnormal inflammatory caspase-related innate immune cytokines and to test whether these polymorphisms are associated with susceptibility to death, organ dysfunction etc. in patients with sepsis. Identification of genetic risk factors can provide new genetic markers of risk prediction and early prevention of sepsis, and a reasonable target of clinaical treatment. Methods: Two sepsis case-control populations from China (299 sepsis patients and 299 controls from Dalian city in Liaoning province, 255 sepsis patients and 260 controls from Zhengzhou city in Henan province.) were recruited, 34 htSNPs (haplotype-tagging SNP, htSNP) covering 11q22.3 caspase gene cluster were genotyped by SNPstream technology. Associations were estimated by logistic regression models, and function of the variants was examined by biochemical assays. Results: Adjusted by sex, age, smoke, drink, chronic disease, APACHEII and etiological factor in log-additive model, rs506601 T allele can increase the risk of the death of sepsis patients (Dalian: OR = 6.83, 95% CI = 1.63-28.67, P = 0.011; Zhengzhou: OR = 5.39, 95% CI = 1.03-28.11, P = 0.05; Combined population: OR = 4.58, 95% CI = 1.61-13.07, P = 0.0059). We characterized the SNP rs506601 A>T change, located upstream of CASP12, as a functional variant because it affected the reporter gene activity, resulting in decreased truncated protein CASP12-S expression. Conclusion: Our studies provide the first association between variants on chromosome 11q22.3 gene cluster and sepsis. These results support 11q22.3 gene cluster as a susceptibility region for sepsis in Chinese but underscore the difference in genetic markers among different ethnic population.