ABCG2 and breast carcinoma: Additionally, expression of BCRP has been reported in normal human tissues (Maliepaard et al, 2001), in a small panel of human tumour samples including two seminoma specimens (both considered BCRP-negative; Scheffer et al, 2000a), and in human breast carcinoma (Kanzaki et al, 2001) and acute leukaemia (Ross et al, 2000).