The NF-κB pathway is activated in CLL patients harboring BIRC3 disruption. Western blot analysis showing BIRC3 expression and NFKB2 processing in purified primary tumor cells from 9 CLL patients carrying wild-type or disrupted BIRC3. The JJN3 (plasma cell leukemia) cell line was used as a positive control for NFKB2 processing and BIRC3 expression. The KMS-12PE cell line (a multiple myeloma cell line) was used as a negative control for NFKB2 processing. Actin was used as a loading control. The histogram shows the relative fold change of BIRC3 expression compared with the BIRC3 expression level observed in the JJN3 cell line (arbitrarily set as 100). The aberrant BIRC3 bands in patients 6550 and 5610 correspond in size to the predicted BIRC3-truncated protein.