|Application:||DNA methylation array analysis|
|Number of samples:||120|
|Release date:||Dec 1 2017|
|Last update date:||Nov 27 2018|
|Diseases:||Tobacco Use Disorder|
|Dataset link||Global Methylation Profiles in Buccal Cells of Long-Term Smokers and Moist Snuff Consumers|
DNA extraction and global methylation profiling was performed by Expression Analysis on Illumina Infinium HumanMethylation450 BeadChip arrays. All data were normalized using Illumina recommended normalization method to reduce the effects of experimental variation. This normalization procedure included background estimation using negative control probes and normalization of intensities to the housekeeping genes with no CpG sites. Beta values (β), which are used to estimate the methylation level of the CpG locus using the ratio of intensities between methylated and un-methylated alleles, were exported from Illumina Genome Studio software and all analyses were performed using the SAS® statistical software package. For normally distributed beta values, we analyzed the data by modeling each individual methylation locus by linear regression with age and race as independent variables.