There is no single marker for the definitive diagnosis of CLL by Immunophenotyping and in general, the diagnosis of CLL is easily achieved in the presence of the characteristic immunophenotyping pattern (CD5+, CD23+, FMC7-, CD22-/CD79b- and weak expression of SmIg) which is based on the Matutes scoring system [29]. This evidence concerns the gene CD5 and B-cell chronic lymphocytic leukemia.