SMAD4 and B-cell chronic lymphocytic leukemia: Our results showed that SMAD-2 and SMAD-4 mRNAs were significantly decreased in the progressive U-CLL subgroup (p = 0.006, n = 28 and p ≤ 0.0001, n = 27, respectively, Mann–Whitney Unpaired test), whereas SMAD-3 and SMAD-7 were not significantly changed (Figure 2).