GSTM1-null and/or GSTT1-null genotypes are associated with the development of grades III–IV thrombocytopenia (Cho et al., 2010) upon combined chemotherapy with rituximab and cyclophosphamide/doxorubicin/vincristine/prednisone or R-CHOP. This evidence concerns the gene GSTM1 and Thrombocytopenia.