Expression And Methylation Status Of SOX7 Gene In Renal Cell Carcinoma

Objective: Renal cell carcinoma is a malignant tumor originated from the renal tubule epithelial system.The incidence of renal cell carcinoma is about 4/10 million,which is a serious threat to the health of Chinese people.AT present,the etiology of RCC is not clear,and may be related to heredity,obesity,smoking,hypertension and antihypertensive treatment.It is found that epigenetic changes can affect gene expression,which may be related to the occurrence and development of tumors.Gene methylation belongs to the category of epigenetics.At present,the relationship between the methylation of DNA gene and tumor has been studied deeply.SOX7 belongs to the SOXF subfamily.As a factor in the SOXF subfamily,SOX7 is involved in the regulation of many developmental processes,such as blood formation,angiogenesis,muscle development,and so on.In recent years,the results show that methylation of SOX7 gene promoter and abnormal expression of SOX7 m RNA in malignant tumors such as lung cancer,breast cancer and liver cancer may be one of the reasons for tumorigenesis and development.However,there is no report about SOX7 in RCC.In this study,we analyzed the relationship between abnormal methylation and the transcriptional expression of SOX7 gene by MSP and RT-PCR.At the same time,the relationship between the results and clinical data was analyzed by statistical software.The purpose of this study was to investigate the role of aberrant methylation of SOX7 gene in RCC preliminarily.Methods:1 In this experiment,all the samples come from The 4th hosipital of He Bei Medical University,which include 58 RCC tissue specimens and 58 corresponding Normal tissue specimens.Reverse transcription polymerase chain reaction(Reverse Transcriptase-PCR,RT-PCR)was used to detect the expression of SOX7 gene.2 Methylation status of promoter region of SOX7 gene was analyzed by methylation specific PCR(Methylation Specific PCR,MSP).3 We use statistical software SPSS20.0 to analyze the experimental data.Results: 1 In RCC and normal tissues,SOX7 has three different methylation states,such as methylated state,hemimethylated state and unmethylated state.2 The positive rate of methylation of SOX7 gene in RCC tissues was 36.2%(21/58)higher than that in normal tissues 10.3%(6/58),and the difference was statistically significant(?2=10.86 P=0.001).In 58 RCC tissues,the methylation rate of SOX7 gene was statistically different in clinical stage(stage I,II and III,IV)(P=0.035),but we got the opposite answer in age(?2=0.015 P=0.559),gender(?2=0.023 P=0.547),tumor diameter(?2=0.037 P=0.547)and Fuhrman nuclear classification(?2=0.514 P=0.773).3 The expression of SOX7 gene in renal cell carcinoma(RCC)was 0.35±0.06,which was lower than that of normal tissues(0.62±0.07)and the difference was statistically significant.There were no significant differences in the expression of SOX7 gene in terms of age(t=1.359 P=0.182),gender(t=-0.490 P=0.626),tumor diameter(t=-1.347 P=0.183),and there was statistical difference in the clinical stage(I,II and III,IV)(t=-2.254 P=0.028).4 In 58 cases of RCC,the expression of SOX7 gene was 0.41±0.05 in methylation positive patients,and in unmethylation patients was 0.63±0.07.The difference was statistically significant(t=-12.506 P=0.000).Conclusions:1 In RCC tissues,SOX7 gene promoter methylation is a frequent event,and the methylation rate of SOX7 gene in renal cell carcinoma was significantly higher than that in normal renal tissues,suggesting that SOX7 gene hypermethylation may be one of the main mechanisms of RCC.2 The expression of SOX7 gene in RCC tissues was lower than that in normal tissues,suggesting that SOX7 gene may be a tumor suppressor gene in renal cell carcinoma.3 In 58 cases of RCC,the expression of SOX7 gene in methylation positive patients was lower than that in unmethylation patients,suggesting that the methylation of SOX7 gene may be an important cause of its transcriptional silencing.