CD38 and B-cell chronic lymphocytic leukemia: In conclusion, (i) by FISH analysis we disclosed genetic lesions in the minor of CD38+ cell fraction in CD38- CLL with low-risk FISH findings, (ii) we provided evidence supporting an association between cryptic genetic lesions in CD38+ cells and disease progression, (iii) we found that genomic complexity and worse outcome were associated with miR-125a-5p down-regulation and, iv) we validated this finding in an independent cohort of untreated CD38- CLL patients with low risk FISH findings.