To definitively establish the role of GSK3β in N1-ICD regulation, we analyzed N1-ICD expression in CLL cells (n = 6) transiently transfected with an empty plasmid as control, or a plasmid containing a constitutively active GSK3β, which has the Serine 9 (S9) mutated to Alanine (S9A) and cannot be phosphorylated, remaining in an activated status [43]. Here, GSK3B is linked to B-cell chronic lymphocytic leukemia.