Association Of RUNX3 Polym Orphisms With Risk And Prognosis Of Bladder Caner

Bladder cancer is one of the common cancers, and the incidence and mortality of bladder cancer is the highest in the urinary cancers. For the past few years, there is an increasing trend in the incidence of bladder cancer worldwide, and this trend is more pronounced in China. Bladder cancer is a disease with a complex etiology, including interactions between genetic factors and environmental factors. Epidemiological survey shows that smoking and occupational exposure are the two most important risk factors for bladder cancer. However, there is still a discrepancy of susceptibility for different individuals to develop bladder cancer. In addition, different patients with same stage have different survival time even under equal treatment, suggesting that genetic variations play important roles in bladder cancer development and prognosis.TGF-βis a multifunctional growth factor that plays very important roles in many cellular functions. The RUNX3 protein coded by RUNX3 gene is an important component in TGF-? signalling pathway. RUNX3 protein binds DNA by partnering with the cofactor, and the resultant complex activates and represses the transcription of target genes. The gastric mucosa of Runx3 null mouse exhibits hyperplasias due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to growth-inhibitory and apoptosis-inducing action of TGF-β, indicating that Runx3 is a tumor suppressor. Meanwhile, RUNX3 interact with other different proteins to display broad biological functions.With completion of Human Genome Project (HGP), it is known that genetic variations play important roles in gene structure and function, and single nucleotide polymorphism (SNP) is the most common type of genetic variations. In the study of molecular genetics, SNP has been widely used as molecular markers for various diseases including cancers. Many studies have shown that SNP could influence susceptibility and prognosis of cancer. As a member of TGF-? signalling pathway, genetic variation of RUNX3 gene could affect the strength of signal in the pathway, thus playing crucial roles in cancer development and prognosis. In the present study, we adopted the strategy of tagging SNP (tSNP), and conducted a hospital-based case-control study and a prospective cohort study respectively to investigate the associations between the polymorphisms of RUNX3 gene and bladder cancer genetic susceptibility and prognosis. Our study searched for potential biomarkers for bladder cancer susceptibility and prognosis, which may provide important clues for individualized prevention, clinical decision and individualized treatment.Chapter I Genetic variants in RUNX3 and risk of bladder cancerThe present study consisted of 368 histopathologically confirmed bladder cancer patients and 368 cancer-free controls. We selected ten common tSNPs from RUNX3 gene and its flanking regions of 2,000bp both upstream and downstream. In the single-locus analysis, we found a significantly increased risk of bladder cancer associated with the SNP7 rs760805 AA genotype (adjusted OR = 1.97, 95%CI = 1.44-2.69), compared with the AT/TT genotypes. In the stratification analysis, this increased risk was more pronounced among subgroups of aged >65 years (2.83, 1.77-4.53), male (2.16, 1.52-3.07), smokers (3.46, 2.16-5.54) and drinkers (2.60, 1.58-4.27).Haplotype-based association analysis revealed that the increased risk of bladder cancer was significantly associated with two haplotypes TATCCCAAAA (2.37, 1.16-4.83) and AGCTTGAGAG (2.70, 1.08-6.72) that included the rs760805 A allele. Multifactor dimensionality reduction (MDR) analysis showed that there was a supermultiplicative interaction between SNP7 and smoking (P = 0.001) and an additive interaction between SNP3 and smoking (P = 0.032). The SNP3 rs11249206, SNP5 rs1395621, SNP7 rs760805, SNP8 rs2236852 and the trichotomized cumulative smoking were the five factors best predicted by the MDR models. When the variables were combined and dichotomized and fitted into the MDR model, the subjects carrying the combined risk stratum had a significantly increased risk for bladder cancer (6.37, 4.57-8.87, P = 7.03×10^-28). These results suggested that the genetic variants in RUNX3 may modulate the risk of bladder cancer.Chapter II RUNX3 polymorphisms and cancer risk: a meta-analysisThree published studies, including 1,259 cancer cases and 2,333 controls were identified in the present meta-analysis. We evaluated the association between two SNPs (SNP1 rs6672420 and SNP7 rs760805) in RUNX3 gene and cancer susceptibility. For SNP1 rs6672420, our result suggested the variant heterozygote genotype AT, was associated with a significantly decreased cancer risk (OR = 0.79, 95%CI = 0.62-0.99), compared with the wild-type homozygote AA. For SNP7 rs760805, the variant homozygote genotype AA was associated with a significantly increased cancer risk (OR = 1.32, 95%CI = 1.07-1.62), compared with the wild-type homozygote TT. Similar result was also observed in recessive model (AA versus AT/TT, OR = 1.47, 95%CI = 1.00-2.16). Moreover, we did not find any significant heterogeneity and publication bias. The results suggested that RUNX3 polymorphisms are associated with cancer susceptibility. Additional well-designed larger studies are required to validate these findings.Chapter III RUNX3 polymorphisms and bladder cancer: from initiation to recurrence, progression, and survivalIn this prospective study, we evaluated the associations between RUNX3 polymorphisms and prognosis of bladder cancer in a cohort of 229 patients with complete follow-up and clinical information. Among the 163 superficial bladder cancer patients, we found that SNP3 rs11249206 C>T polymorphism was significantly associated with the progression time of patients (Log-rank P = 0.020). Univariate and multivariate Cox regression analysis showed that patients carrying the TT genotype had a significantly increased progression risk, compared to those with CC/TC genotypes. In addition, SNP3 rs11249206 C>T polymorphism was also significantly associated with the survival time of all bladder cancer patients (Log-rank P = 0.024). Cox regression analysis revealed that patients carrying the TT genotype had a significantly increased death risk. When these ten selected tSNPs were took into consideration together, the progression and death risk increased significantly as the number of risk allele increased.Our results suggested that the genetic variants in RUNX3 were associated with prognosis of bladder cancer and SNP3 rs11249206 C>T may serve as a promising prognostic biomarker for bladder cancer. Melanoma is a malignant skin cancer originated from melanocyte. The incidence of cutaneous malignant melanoma is increasing more rapidly than that of any other tumors. The development of melanoma is the result of environmental risk factors and genetic factors. At present, excessive ultraviolet radiation is a well known risk factor for melanoma. Although early melanomas are curable with surgical excision, patients with metastatic melanoma have a poor prognosis, and it is responsible for 80% of deaths from skin cancers.Tumor metastasis is the main cause of death in cancer patients. During this process, many moleculars are activated and interact with each other, which form a complex signal network. Cell migration is a hallmark of tumor metastasis, and rearrangement of cystoskeleton is a prerequisite for cell migration. Thus, comprehensive understanding of tumor metastasis related signal network is essential for tumor metastasis prevention and improving quality of life.It is reported that some key members in the TGF-??signalling pathway play important roles in melanoma cell migration. To date, the association between expression level of RUNX3 and melanoma migration has not been reported. Our result showed that overexpression of RUNX3 could inhibit migration of melanoma cell. In addition, RUNX3 expression was evaluated by immunohistochemistry in two sets of tissue microarrays. Positive RUNX3 expression decreased gradually as melanoma progresses. Loss of RUNX3 expression was correlated with a worse 5-year survival of melanoma patients in both training and validation sets. Furthermore, loss of RUNX3 expression was also correlated with a poor 5-year survival in primary melanoma and metastatic melanoma patients. Multivariate Cox regression analysis revealed that positive RUNX3 expression is an independent prognostic factor to predict melanoma patient outcome.Our findings indicate that RUNX3 could inhibit melanoma cell migration and plays an important role in melanoma pathogenesis, which may serve as a promising prognostic marker for melanoma.