Jensen et al (1997) observed that some small-cell lung cancer (SCLC) cells with P-gP overexpression were more sensitive to gemcitabine and the structurally related deoxycytidine analogue 1-β-D-arabinofuranosylcytidine (cytarabine, ara-C), although Grant et al (1995) observed crossresistance to ara-C in a P-gP-overexpressing leukaemia cell line. Here, PGP is linked to leukemia.