We treated the TSLP-negative human ovarian cancer cell lines (A2780, IGROV-1, KURAMOCHI and TOV21G) with DNA methyltransferase inhibitor (5-aza-2′-deoxycytidine; AZA), histone deacetylase (HDAC) inhibitor (Trichostatin A; TSA) or histone methyltransferase (HMTase) inhibitor (BIX01294). This evidence concerns the gene PRDM9 and ovarian cancer.