ABCB1 and ovarian adenocarcinoma: Indeed, we have previously shown that ABCB1 expression remains unchanged after TSA treatment of the multidrug-resistant human ovarian adenocarcinoma cell line OV1/VCR, in which ABCB1 promoter is slightly hypermethylated compared to its sensitive IGROV1 counterpart (Yatouji et al, 2007).