At the time of diagnosis, the median level of β2M in total patient's group was 1,86 mg/L (range: 0,51–4,25 mg/L), in the group of aggressive lymphomas β2M was 1,82 mg/L (range: 0,51–4,25 mg/L), in the group with extranodal disease presentation β2M was 1,67 mg/L (range: 0,51–3,85 mg/L), and in the group with nodal disease presentation β2M was 1,89 mg/L (range: 1,13–4,25 mg/L). The gene discussed is B2M; the disease is lymphoma.