Expression of resistance proteins in samples taken both at initial diagnosis (I) and at relapse (R) of the same patients. Depicted are the FI for P-gp, MRP, and LRP using, respectively, MRK16 (n = 7), MRPr1 (n = 8), and LRP56 (n = 9). Each patient is indicated by the same symbol for each resistance protein. Differences in FI are not significant.