OVCAR-3 has been shown to demonstrate progesterone receptor expression and is capable of cellular inhibition by Mifepristone which may have implications for cytotoxic assays assessing progesterone co-culture; therefore, an independent tumor target widely used in NK cell biology (K-562) was preferentially selected using an alternative cytotoxic assay (NovoCyte®). This evidence concerns the gene PGR and neoplasm.