The Analysis Of DNA Methylation And Histone Modification Of Tumor Suppressor Genes And Proto-Oncogenes

Cancer is a complex process. Previous researchs have indicated that it is closely related to the mutations and modifications of tumor suppressor genes and proto-oncogenes. In this article the tumor suppressor genes and proto-oncogenes flanking transcription start site and transcription termination site around 2000bp are selected as the research object, the differences between the distributions of the DNA methylation of tumor suppressor genes and proto-oncogenes in cancer cells and normal cells are explored. The results show that the DNA methylation level of tumor suppressor genes in cancer cells is higher than normal cells. And the distributions of DNA methylation in tumor suppressor genes are different from proto-oncogenes. Tumor suppressor genes are mainly located in the transcription start site 1000 bp, and distributions of DNA methylation in proto-oncogenes are wider than the distribution of tumor suppressor genes. Finally, the DNA methylation level in the TSS and TTS flanking the regions of each tumor suppressor gene and proto-oncogeneis is studied, two special suppressor gene RUNX3, WT1 are found out. DNA methylation levels of the two genes are higher in the cancer cells than in the normal cells. And the two genes can encode the transcription factors, which have similar biological function.Second, Distribution location of the methylation of tumor suppressor genes and proto-oncogenes has been carried on the correlation analysis, finding tumor suppressor genes distance from itself position lbin to 4bin, most genes present positive correlation, and position of 2 bin has a strongest correlation coefficient. When beyond 5 bin location, there are many negative correlation. Most proto-oncogene present negative correlation, the location of the distribution and the correlation coefficient is low.Finally, the principal component analysis and factor analysis are done for histone modifications and DNA methylation of tumor suppressor genes and proto-oncogenes.We find that the correlation coefficients between histone modifications and DNA methylation of oncogenes are higher than proto-oncogene. Based on histone modification and DNA methylation level, a multiple linear regression model is constructed to predict gene expression level.