Methylation And Expression Of SOX7 Gene In Oral Squamous Cell Carcinoma

Object: Oral squamous cell cancer(OSCC)is one of the most common type of head and neck cancer. Roughly speaking, the incidence of OSCC is around 3.6/100000~8.0/100000 in China. Although we have taken comprehensive treatment with the patients who are with OSCC, we are disappointed at the therapeutic results that the rate of five-year survival in the patients of OSCC still remains at 60%.Because of the high mortality and the occurrence of second primary cancer, surgeons have been explored effective measures to treat OSCC. Several studies have suggested that tobacco, alcohol and infection of HPV are high risk factors of OSCC development. Recently multiple researches show that epigenetic changes have been found in OSCC and other cancers. Meanwhile other data proves that there is a correlation between the occurrence of cancer and epigenetic changes which could lead to genomic instability and alteration of gene expression.SOX7 is a transcription factor belonging to the SOX family SOX7,together with SOX17 and SOX18, comprises the SOXF subgroup and helps mediate various developmental processes including a role in the regulation of cardiogenesis, vasculogenesis, endoderm differentiation and myogenesis and so on. It is reported that there are abnormalities in methylation status and mRNA expression of SOX7 gene in kinds of cancer such as lung cancer, gastric cancer, prostate cancer, which may be related to oncogenesis. Now we haven't found SOX7-related report in OSCC. Therefore, in order to investigate the relationship between methylation status and mRNA expression of SOX7 gene and OSCC we perform the experiments.We hope our experimental data would provide reference for further experiment.Method:1 In this study,whole samples come from The 4th hosipital of HeBei Medical University, which include 48 OSCC tissue specimens and 48 corresponding Normal tissue specimens taken from the normal surgical margin of the carcinoma. The methylation status of SOX7 gene in OSCC and Normal tissue specimens was identified by methylation-specific Polymerase Chain Reaction(MSP). Meanwhile the correlation between the methylation status of SOX7 gene and clinical parameters was analysed.2 Reverse Transcrpition Polymerase Chain Reaction(RT-PCR) was used to detect the relative mRNA expression of SOX7 gene in 48 OSCC and Normal tissue samples. And we also analysed the relationship between mRNA expression of SOX7 gene and clinical data.3 All experimental datas were processed by SPSS20.0.Result:1The experimental results shown that the incidence of SOX7 gene methylation in OSCC tissues was 43.75%(21/48),which was significantly higher than those in normal tissues 20.83%(10/48)(?2=5.765,P=0.016),and the difference between two groups was considered statistically significant; 2 By analysis of the relationship between methylation status of SOX7 gene and clinical parameters in OSCC,we found that incidence of SOX7 gene methylation in?+?group was 23.81%(5/21),which was significantly lower than ?+?group 59.26%(8/23)(?2=6.032,P=0.014).The positive rate of methylation of SOX7 genes in lymph node metastasis group was 63.16%(12/19),which was higher than that in none of lymph node metastasis group 31.03%(9/29)(?2=4.813,P=0.028). The positive rate of methylation of SOX7 genes in moderate and high differentiation group was 31.25%(10/32),which was lower than that in none of lymph node metastasis poor group 68.75%(11/16)(?2=6.095,P=0.014). But the positive rate of methylation in male group was 50%(14/28)and female group was 35%(7/13)(?2=1.067,P=0.302),and there is no significance in statistics. The similar results were found in age, smoking and drinking, that is, positive rate of methylation of SOX7 gene in OSCC Patients weren't statistically associated with age, smoking and drinking(P>0.05);3The experimental results shown that relative mRNA expression of SOX7 gene in OSCC tissues was 0.41�0.20,which was significantly lower than those in normal tissues 0.74�0.40,and the difference between two groups was considered statistically significant(t=-4.884,P<0.001);4By analysis of the relationship between relative mRNA expression of SOX7 gene and clinical parameters in OSCC, we found that mRNA expression of SOX7 gene in?+?group was 0.48�0.16,which was significantly higher than ?+?group0.35�0.18(t=2.765,P=0.003).The mRNA expression of SOX7 gene in lymph node metastasis group was 0.34�0.14,which was higher than that in none of lymph node metastasis group 0.45�0.20(t=-2.162,P=0.036).The mRNA expression of SOX7 gene in moderate and high differentiation group was 0.46�0.16,which was higher than that in none of lymph node metastasis poor group 0.30�0.16(t=3.189,P=0.003).The similar results which were found in research of methylation status of SOX7 gene, that is, mRNA expression of SOX7 gene in OSCC samples weren't statistically associated with age, smoking and drinking(P>0.05). 5 48 OSCC samples were divided into two groups, which one was methylation and another one was unmethylation. The mRNA expression of SOX7 gene was 0.34�0.18 in methylation group, which was lower than that unmethylation group 0.46�0.18(t=-2.353,P=0.023).There was significance in statistics.Conclusion:1 Methylation of SOX7 gene may serves as one of mechanisms of oncogenesis.2 The results demonstrate that methylation of SOX7 gene may contribute to decrease in expression of SOX7 mRNA.3 The results also indicate that methylation status and mRNA expression of SOX7 gene are constantly changing as the patient's condition changes, and maybe it is related to disease progression. These data also show that hypermethylation and lower expression of SOX7 gene may be act as index of evaluation of prognosis in OSCC patients, but it is still need to further research to make a conclusion.