In a large-scale audit of patients in the United Kingdom receiving chemotherapy, which included 856 patients with ovarian cancer, the proportion of ovarian cancer patients with anaemia (haemoglobin (Hb) <11 g dl−1) rose from about 25% after chemotherapy cycle 1 to 50% after cycle 6, despite 41% of these patients having received at least one blood transfusion during treatment (Barrett-Lee et al, 2000). Here, GSTM1 is linked to anemia (phenotype).