CD38 and B-cell chronic lymphocytic leukemia: As the prognosis of patients with negative CD38 expression and/or unmutated IGHV genomic sequences is substantially different from the prognosis of patients showing positive CD38 expression and/or mutated IGHV, Kaplan-Meier OS analysis was performed in substantially different prognostic subgroups of CLL patients, stratified according to each one of these established prognostic factors, in order to evaluate the potential additional prognostic value of miR-155-5p expression.