To this end, using intracellular phospho-flow cytometry, we analyzed pERK1/2 and pNF-κΒ p65 levels in CLL cells supplemented with calcitriol for 24 h and observed a significant increase in pERK (n = 8, FD: 1.6, p < 0.01) (Figure 3A,B), hence contrasting the phosphorylation of NF-κB that was significantly decreased (n = 6, FD: 3.4, p < 0.05) (Figure 3C,D). This evidence concerns the gene NFKB1 and B-cell chronic lymphocytic leukemia.