ABCB1 and neutropenia: Concerning the toxicity profile, the analysis of 132 patients with “gene-gene interaction” models (MDR -multifactor dimensionality reduction) analysis evaluating CYP3A5*3, ABCB11236C>T and ABCB1 2677G>T/A, ABCB1 3435C>T and CYP1B1*3 variants, showed a significant association with treatment response, but also with anemia of grade 2-4, and the dose delay/reduction induced by neutropenia (P = 0.024, P = 0.004, P = 0.026), respectively [189].