For sake of evaluation of the predictive value of cystatin C as a marker of course of the disease, the cystatin C levels were compared with established biochemical parameters (C reactive protein (CRP), beta-2 microglobulin (β2M), lactate dehydrogenase (LDH) levels/activities), with clinical parameters of disease progression (the presence of B symptoms, clinical stage, age, and international prognostic index (IPI)), and with suggested prognostic factor in patients with lymphoma [9] (the levels of cytokine interleukin 6 (IL-6)). The gene discussed is IL6; the disease is lymphoma.