The molecular mechanisms associated with DNMT3B expression were then further investigated by comparing DNA methylation levels in high-DNMT3B-expressing tumours (DNMT3B+) versus low-DNMT3B-expressing tumours (DNMT3B−) samples in the TCGA–BRCA public dataset, which combines expression and methylome data from the same breast cancer tumours, and then confirmed in an independent cohort. The gene discussed is DNMT3B; the disease is breast cancer.