FOS and cancer: Among the genes with significant DNA methylation loci, we observed significant enrichment of genes associated with cell cycle, cellular growth and proliferation, including FOS, LMNA, RUNX1, SLC9A3R1, SNTB2, STAT5B, SUZ12, UGCG, VEGFA, AK4, NCOA6, NCOR2, SOX4, EPB41L1, EHD1 and SNTB2. This suggests an important role in tamoxifen resistance of epigenetic alteration of genes involved in growth and proliferation of cancer cells.