Also poor metabolic activity due to CYP2C8*3 (399R) and CYP3A4*1B (392 AA/AG) causes pharmacokinetic problems, and lower expression of the XRCC3 316AG/GG phenotype probably interferes with DNA replication of neoplastic cells and less likely with that of hematopoietic cells, resulting in severe neutropenia, as previously observed in a Caucasian population (Qiu et al., 2013). The gene discussed is CYP3A4; the disease is Decreased total neutrophil count.