Recently, van Hoesel et al. [23] studied LINE-1 methylation index during breast cancer progression from normal breast to ductal hyperplasia, ADH, DCIS and stage I IBC using absolute quantitative assessment of methylated alleles PCR assay and showed the most profound and statistically significant decrease of LINE-1 methylation index during transition from ADH to DCIS. This evidence concerns the gene AVP and ductal breast carcinoma in situ.