The Preliminary Study On Relationship Between Multiple Gene Aberrant Methylation And Different Molecular Subtypes Of Breast Cancer

Objective:Aberrant DNA methylation patterns usually occur at an early stage of breast cancer development. Breast cancer is a malignant tumor with a high degree of heterogeneity on a class of molecules.Even if the tissue morphology is identical, the changes in molecular genetic are not the same, which leads to a different molecular subtype. The purpose of this experiment is to study the level of methylation of multiple genes in different molecular subtypes of breast cancer, and to explore the relationship between gene methylation and breast cancer molecular subtypes.Methods:We have used candidate-gene approach to investigate the methylation of48target genes in breast cancer. A novel microfluidic Access Array system combined with bisulfite DNA treatment have been applied for next generation sequencing to detect DNA methylation. The tumor tissue and Paired normal tissues DNA from83breast cancer patients were bisulfite treated and amplified with Access Array then sequenced on Illumina MiSeq next-gen sequencer. Depending on the different molecular subtypes of samples, we have performed a statistical analysis on the levels of genes using Kruskal-Wallis Rank Sum Test, with FDR correction for P value calculation.Results:We have successfully sequenced45of the48target genes, with only3genes failed due to primer amplification efficiency issues.1、. The integrated methylation level of Luminal A-type group, Luminal B-type group, HER2overexpression group, Basal-like type group were:0.054±0.036,0.060±0.035,0.034±0.033,0.017±0.019, P=0.012(<0.05), with a difference statistically significant.2、Among the45target genes, we found that methylation levels of three genes were significantly different among different molecular subtypes of breast cancer: ADAMTSL1, PTGS2, RUNX3.Conclusion:1、The overall methylation level of45genes in different molecular subtypes of breast cancer showed significant differences, suggesting that aberrant methylation of the genes may affect the characteristics of the molecular biology of breast cancer in a certain extent, resulting in different molecular subtype.2、The gene methylation levels of ADAMTSL1, PTGS2, RUNX3are significantly different in different molecular subtypes of breast cancer, suggesting that they may be potential molecular markers for breast cancer molecular classification。...