Following the same principles, in 2012 a multicenter study involving 593 SMZL patients from different international cancer centers, known as the Splenic Marginal Zone Lymphoma Working Group (SMZL-WG), determined the unfavorable predictor value of Hb < 95 g/L, platelets < 80 x 109/L, LDH > UNV and presence of extra hilum-splenic lymphadenopathy for symptomatic progression-free survival at 5 years. This evidence concerns the gene GSTM1 and cancer.