Figure 2: HPLC analyses of relative changes in intra- and extracellular dFdU levels following pharmacologic efflux inhibition. Samples treated with gemcitabine without pretreatment of verapamil or probenecid was used as a control and all the others are in reference to the control as 100%. Pretreatment with probenecid before gemcitabine treatment resulted in statistically significant increases in intracellular and decreases in extracellular dFdU levels in all the studied cell lines except IGROV1; statistically significant values (p<0.05) are presented; n=3.