Epigenetic marks such as DNA methylation (DNAm) of cytosine residues in the context of CpG dinucleotides, have been extensively characterized in EOC tumor tissue and have been shown to differ between histological subtypes of ovarian cancer [4], associate with patient clinical outcomes including survival time [5] and progression [6], and have led to identification of inherited variants in HNF1B (hepatocyte nuclear factor 1 homeobox B) as a subtype-specific susceptibility gene [7]. This evidence concerns the gene HNF1B and ovarian cancer.