In parallel with a PCNSL study based on European populations which found that pretreatment anemia (defined as <12 g/dl in women and <13 g/dl in men) was robustly associated with poor prognosis (26), our study had a different cutoff value of ≤11.1 g/dl in all patients and found that patients with a low Hb level had an inferior outcome in PFS. This evidence concerns the gene GSTM1 and anemia.