Among the genes that change in expression within the tumour as a whole as a result of clonal selection upon docetaxel treatment, we identified a number of genes related to glutathione synthesis and conjugation including Mgst2, Esd, and Gclm (Figure 5a and b), that may endow resistant clones with greater ability to resolve reactive oxygen species (ROS) induced by docetaxel (Alexandre et al., 2007). The gene discussed is ESD; the disease is neoplasm.