For example, the detection of methylated ctDNA at the promoter of HOXA9 (previously shown to be a poor prognostic factor) has been associated with poorer clinical outcomes in patients with platinum resistant ovarian cancer, with a median OS of 9.5 months vs. 19.4 months in patients without detectable methylation in HOXA9 [88]. This evidence concerns the gene HOXA9 and ovarian cancer.