The Association Study Of Single Nucleotide Polymorphism In HIF1A Gene With Prognosis Of Hepatocellular Carcinoma Patients

Background：Primary liver cancer is one of the most common malignancies. Thelatest data showed that about700，000new cases of liver cancer were diagnosed eachyear all through the world， accounting for6%of the total new cancer patients， rankedfourth in the incidence of all malignancies. Because of its high malignancy and poorprognosis， the mortality of liver cancer was always top in all types of cancer inworldwide. In China，new cases of primary liver cancer accounted for more than55%ofthe new cases all the world， in which， hepatocellular carcinoma (HCC) represents themajor histological type and accounted for about90%. In recent years， there are feweffective preventions and treatment strategies for HCC patients， especially for patientswith advanced stage， causing no significantly prolonged survival and reducedrecurrence rate.The main treatment for HCC includes surgery and transcatheter arterialchemoembolization (TACE). Most cancer patients have been diagnosed in advanced stage and missed the best time for treatment， have a limited efficacy. In order toimprove the accuracy of early detection and diagnosis in liver cancer patients， someclinical prognostic indicators have been found. Traditional prognostic indicators of HCCinclude tumor size and number， AFP level， tumor grade and stage， differentiation，whether with portal vein invasion， etc. however， those indicators are still difficult toapply to HCC’s prognostic evaluation and individualized treatment. With thedevelopment of molecular biology， finding new markers from cellular and molecularlevel to tumor diagnosis is the way for future development. Currently， some studiesshowed that the genetic factor plays an important role in tumor proliferation，progression and metastasis. And most importantly， polymorphisms of liver cancerrelated gene may associate with development HCC. We wish to find new and moreeffective tumor markers guiding clinicians to accurately evaluate the prognosis， developa reasonable treatment plan and finally improve the survival of HCC patients.Hypoxia inducible factor-1(HIF-1)， a transcription factor， consists of twosub-units–HIF-1α and HIF-1β， both of which belong to the basic loop-helix Per-Arylhydrocarbon nuclear translocator-Sim zprotein family. HIF-1coordinates the response tohypoxia in normal and tumor tissues， which allows the cell to adapt and survive inhostile environment. It immortalizes tumor cells by inducing the expression of key genesinvolved in cancer biological processes，including angiogenesis，glycolysis，invasion，and metastasis. A series of studies have reported that the overexpression of HIF-1α isassociated with an aggressive phenotype and the increased mortality in many cancertypes， including HCC， but the exact mechanism is unclear.Single nucleotide polymorphism (SNP) is one of the most common inherited formsof human variation which means a single nucleotide variation at the genomic level， andits minimum frequency of variation is1%. SNP has been identified that related to avariety of diseases progress and prognosis. Therefore， confirm the mechanism betweenSNP and diseases may be of great valued for the screening， diagnosis， prevention andtreatment of disease. Similarly， HIF1A gene SNPs associated with a variety of tumors.One study found that HIF1A gene locus SNP C1772T (rs11549465) and G1790A (rs11549467) are related to the risk of colorectal cancer. Another study found thatrs2057482SNP associated with high risk of colorectal cancer and oral squamous cellcarcinoma patients with rs11549467variant alleles more likely to recurrence than thewild type. The report between HIF1α gene SNP and other tumors is not too much. Untilnow， there is no report about the relationship between HIF1α gene SNP and HCCprognostic. In recent years， SNP genotyping technology has made remarkable progress，so that clinical perform SNP detection became easier to implement.Surgery is a potentially curative treatment for liver cancer， especially in patientswith early stage. When the patients with advanced stage， surgery should not beperformed， TACE therapy is the main treatment. However， there are significantdifferences in treatment to part of patients with similar clinical pathological features aftersurgery or TACE， and it may be related to genetic polymorphism. Therefore， identifythese significantly gene locus associated with prognosis has a positive meaning forassessing the patient’s condition， prognosis and the development of rational treatmentplan.Aims: The aim of this study is to investigate the predictive role of single nucleotidepolymorphisms (SNPs) in HIF1A gene in HCC patients’ overall and recurrence freesurvivals.Methods: We genotyped three functional SNPs (rs2057482， rs1957757andrs2301113) in HIF1A gene and assessed their associations with clinicopathologicalparameters and prognosis of492surgical HCC and448TACE HCC patients. SNPgenotyping was performed using MassARRAY platform which based on MALDI-TOFmass spectrometry technology. Then we did statistics analysis by using Cox regression，Kaplan-meier survival curve and log-rank test to find the association of SNP with clinicaloutcome of HCC patients.Results:①The patients with variant alleles (CT and TT genotypes) of SNPrs2057482had a significantly lower recurrence risk (HR=0.76，95%CI，0.58-0.95，P value=0.028) when compared with patients with the CC genotype. There was nosignificant association between another two SNPs and clinical outcomes of HCC patients. In stratified analysis， the protective effect of rs2057482variant genotype was moreevident in patients with adverse strata， compared with patients with favorable strata.②For HCC with TACE treatment， the stratified analysis found that thevariant-containing genotypes (WV+VV) of SNP rs2301113exhibited a significantassociation with a better overall survival in HCC patients who had tumor size smallerthan5cm in multivariate analysis of Cox proportional hazard model (hazard ratio [HR]，O.58，95%confidence interval [CI]，0.35-0.96，P=0.036). With a similar result, in thepatients taken single tumor subgroup， the variant-containing genotypes (WV+VV) ofSNP rs2301113exhibited a significant association with a better overall survival inKaplan-Meier curve analysis (log-rank P=0.048)， comparing to those carryingwild-type genotype.Conclusion:①SNP rs2057482in HIF1A gene is significantly associated withclinical outcomes of Chinese HCC patients after surgery， especially in those withaggressive status， which warrants further validation in other patient populations.②SNPrs2301113in HIF1A gene may serve as an independent prognosis biomarker foradvanced HCC patient with TACE treatment， further large population study validatinginvestigation is warranted.