High levels of ABCC1, ABCC2, ABCC3 and ABCC4 were found in HB cell lines and HB specimens, and interestingly, higher expression of ABCC4, but not of other ABCC genes was observed in HB subtypes with a more aggressive phenotype (C2 vs. C1) [10]. This evidence concerns the gene ABCC1 and hemoglobin measurement.