SMAD4 and B-cell chronic lymphocytic leukemia: In agreement with previous results highlighting the role of miR-26b-5p on SMAD-4 expression [34], our results show that inhibition of miR-26b-5p in primary CLL cells significantly increases the percentage of cells expressing SMAD-4 (Figure 4B), (p = 0.031, Wilcoxon signed-rank test, n = 7).