Van den Heuvel-Eibrink et al., compared ABCB1, ABCC1, LRP, and ABCG2 mRNA levels in 20 leukemia samples at diagnosis or relapse, observing significantly higher ABCG2 mRNA levels at relapse (median 1.7-fold, p = 0.04). The gene discussed is ABCG2; the disease is leukemia.