Survival analysis also confirmed CLL patients with MRD < 1 %, LDH < 220 U/L, achieving CR or PR, β2-MG <3.5 mg/L and non high-risk cytogenetic abnormality had superior outcome compared to control patients, suggesting CLL patients with β2-MG < 3.5 mg/L, LDH < 220 U/L, ZAP-70 negative, and non high-risk genetic abnormality could be more appropriate candidates for rituximab-based therapy. The gene discussed is ZAP70; the disease is B-cell chronic lymphocytic leukemia.