ABCG2 and cancer: The in vitro incubation of the ABCG2 overexpressing cancer cells lines, H460/MX20 and S1-M1-80, with 0.3 μM of MK-2206 decreased the IC50 values of 1) mitoxantrone by 14.6 and 16.0-fold; 2) SN-38 by 8.5 and 2.2-fold and 3) topotecan by 9.7 and 2.8-fold, respectively.