NUDT15 and Decreased total leukocyte count: Current studies suggest that polymorphism of NUDT15 is significantly associated with leukopenia or myelosuppression (Moriyama et al., 2016; Chao et al., 2017; Kim et al., 2017; Fei et al., 2018; Kakuta et al., 2018; Wang et al., 2018; Fan et al., 2019; Kang et al., 2020).