ABCB1 and neoplasm: There is growing evidence that non-tumour components of ascites are significant in driving chemoresistance.62 For example, cholesterol in ascites upregulates the expression of the multidrug resistance protein 1 (MDR1) efflux pump in ovarian cancer cell lines,63 whereas cholesterol depletion inhibits cisplatin resistance.63 However, cholesterol depletion did not affect resistance to paclitaxel in most cell lines studied.