Mutation Of VEGFR2 Gene In Osteosarcoma And Its Correlation With Clinicopathological Factors

?Objective?In this study,the mutation of VEGFR2 gene in osteosarcoma tissue samples was detected,and the relationship between VEGFR2 gene mutation and various clinical and pathological factors of osteosarcoma patients was analyzed in order to find out gene targets which could help to accurately assess and improve the prognosis of patients,and explore a new way to evaluate the prognosis and treatment of osteosarcoma.?Methods?1.DNA was extracted from 28 osteosarcoma tissue samples,which were collected from the the bone tumor center of Shenzhen Second People's Hospital during January 2010 to May 2017,using the QIAGEN QIAamp DNA Mini Kit kit and following its standard protocol.2.The DNA library was constructed and purified according to the Ion Ampliseq Library Kits 2.0 protocol.3.The preparation and enrichment of the sequencing template was performed according to the standard technology of Life Technology Cancer Panel and then sequenced on the Ion Torrent platform.4.Analyze the results of sequencing data and use statistical methods to analyze the relationship between the VEGFR2 gene mutation and the age,sex,tumor location,clinical stage,pathological type,pathological fracture,alkaline phosphatase level,lung metastasis,recurrence,and survival status of patients with osteosarcoma.Kaplan-Meier and log-rank tests were used to analyze the relationship between VEGFR2 gene mutation and 5-year overall survival.And GraphPad Prism6.0 software was used to draw the survival function curve.?Results?1.A total of 27 samples of 28 osteosarcoma samples were found to havemutations in the VEGFR2 gene,and the total mutation rate of the VEGFR2 gene was 96.43%.2.Four mutation sites of VEGFR2 gene were detected in 28 cases of osteosarcoma tissue samples,including rs10006115,rs3214870,rs7692791 and rs1870377,each site mutation rate was 10.71%,21.43%,71.43%,75.00%.Among them,rs10006115,rs3214870 and rs7692791 were intron mutations,and rs1870377 was a non-synonymous mutation in exons(p: Q472H).3.The mutation rate of rs1870377 was 85.7% in relapse-free patients and42.9% in relapsed patients.Therefore,the mutation rate of rs1870377 in relapse-free patients was significantly higher than that in relapsed patients.The difference was statistically significant(P<0.05).However,the mutation rate of rs1870377 in age,sex,tumor location,Enneking stage,pathological fracture,alkaline phosphatase level,pulmonary metastasis and pathological type of osteosarcoma patients were not statistically different(P >0.05).And the mutation rates of rs10006115,rs3214870 and rs7692791 in all clinical and pathological factors were not statistically different(P>0.05).4.The mutation rate of rs1870377 locus was 88.9% in surviving patients and 50% in death patients.Therefore,the proportion of rs1870377 locus mutations in survivors was significantly higher than that in death patients.The difference was statistically significant(P<0.05).However,the mutation rates of the rs10006115,rs3214870,and rs7692791 loci were not statistically different in the survival subgroups(P >0.05).5.The 5-year overall survival of patients with rs1870377 mutation in the VEGFR2 gene was significantly higher than that in patients without the mutation(P<0.05).However,there was no significant difference in 5-year overall survival between patients with rs10006115,rs3214870,and rs7692791 mutations and those without mutation respectively(P>0.05).?Conclusion?The mutation rate of VEGFR2 gene rs1870377(p:Q472H)in patients with osteosarcoma without recurrence was significantly higher than that in patients with relapse.The mutation rate of VEGFR2 gene rs1870377(p:Q472H) in the surviving patients was significantly higher than that of death patients.And the 5-year overall survival of patients with this mutation was significantly higher than those without the mutation.This reveals that the VEGFR2 gene rs1870377(p:Q472H)mutation may be associated with a decreased risk of osteosarcoma recurrence,as well as beneficial for survival in patients with osteosarcoma,suggesting that the rs1870377 locus of the VEGFR2 gene may be a potential therapeutic target for targeted drugs,and may be a marker for evaluating patients with osteosarcoma with a better survival prognosis.