We collected the following clinical and laboratory parameters: age at diagnosis, gender, Rai stage, bulky lymphadenopathy (splenomegaly ≥8 cm below the costal margin or lymph nodes ≥5 cm), white blood cell (WBC), prolymphocyte, and platelet counts, hemoglobin level, serum lactate dehydrogenase (LDH) and β2-microglobulin levels, hypogammaglobulinemia, CLL score [20], surface immunoglobulin (IG) light chain isotype, CD38, IGHV somatic mutation status, ZAP70 protein expression, and cytogenetic complexity (defined as ≥3 abnormalities). This evidence concerns the gene ZAP70 and Splenomegaly.