The genes with the 4 highest mutation frequencies were particularly considered, including IGLL5, NOTCH1, MYD88, and TP53. The association between these four mutated genes in CLL and molecular prognostic factors (n=22 in the analysis of FISH results, n=22 in the analysis of karyotyping results, and n=31 in the analysis of unmutated IGHV) was analyzed (Table 4). This evidence concerns the gene IGLL5 and B-cell chronic lymphocytic leukemia.