Western blots of cell lysates performed with antibodies specific to the C- (C-Ab) or N- (N-Ab) termini of NPM1 revealed fragments of degraded NPM1 protein (CF and NF, respectively) and a reduction in the overall expression of NPM1 as compared with its expression in a variety of other leukemia and lymphoma cell lines (K562, Raji, Karpas 299 and SU-DHL-1) (Figure 1A). Here, NPM1 is linked to leukemia.