The IgM secreting cell line BCWM.1 (17 (link), 18 ) was a kind gift from Dr. Steven Treon (Dana Farber Cancer Institute, Boston, MA). MWCL-1 cells (19 ) were a kind gift from Dr. Stephen Ansell (Mayo Clinic, Rochester, MN) and RPCI-WM1 cells (20 (link)) were kindly provided by Dr. Asher Chanan-Khan (Mayo Clinic, Jacksonville, FL). All cells were grown in RPMI-1640 supplemented with 10% FBS and penicillin/streptomycin. The GLI1/2 inhibitor (GANT61) and HH inhibitor (Cyclopamine) were obtained from EMD Millipore (Billerica, MA). The pan-caspase inhibitor (Q-VD-OPh) and all primers were obtained from Sigma-Aldrich (St. Louis, MO). β-actin antibody was obtained from Novus Biologicals (Littleton, CO). IL-6Rα antibody for western blot was from Santa Cruz Biotechnology (Dallas, TX). FITC-conjugated Annexin V was obtained from BD Biosciences (San Jose, CA) and propidium iodide was from Sigma-Aldrich.