Hematological toxicities such as neutropenia grade 4 (lasting for ≥5 days), febrile neutropenia of grade ≥3 (absolute neutrophil count <1.0 × 109/L with ≥38.5°C fever), and thrombocytopenia of grade 4 (lasts for ≥5 days) linked with heavy bleeding or requiring platelet transfusion reported during the treatment period of olaparib in both MGMT methylated and methylated patients (Fulton et al., 2018). This evidence concerns the gene MGMT and neutropenia.