Because P-glycoproteins were expressed at levels sufficient to confer the overactivated drug efflux in the MDR ovarian cancer cells as shown above, accumulation of Oregon green-488 paclitaxel (Ore-PTX), which is a fluorescent paclitaxel conjugate as well as a fluorescent substrate of P-glycoproteins, was assessed on the siRNA@PLGA NPs-pretreated SKOV3-TR cells using confocal microscopic images. This evidence concerns the gene ABCB1 and ovarian cancer.