ABCG2 and breast adenocarcinoma: The results summarized in Table 2 revealed IC50 values ranging from 2.71 μg/mL (towards glioblastoma U87MG.ΔEGFR cells) to 10.30 μg/mL (towards breast adenocarcinoma MDA-MB-231-BCRP cells) for AAB, from 3.43 μg/mL (towards U87MG cells) to 10.77 μg/mL (towards resistant colon carcinoma HCT116 (p53−/−) cells) for AAR and from 0.11 μg/mL (towards CCRF-CEM cells) to 108 μg/mL (towards P-glycoprotein-over-expressing CEM/ADR5000 cells) for doxorubicin on the 8 other cancer cell lines studied.