SET mRNA levels in B-cell chronic lymphocytic leukemia (CLL) were 11.2 ± 2.7-fold higher than the mean of normal B cells, and immunoblots from the same samples showed that both the α-isoform and the β-isoform of SET protein, which result from alternative splicing, were higher in CLL than in normal B cells. Here, SET is linked to B-cell chronic lymphocytic leukemia.