BCL2 and cancer: Furthermore, by showing that the IP3R2 protein levels correlated with the sensitivity to BIRD-2 in the following rank order: KARPAS-422 > SU-DHL-4 > OCI-LY-18 > Ri-1 > SU-DHL-6 > TOLEDO > OCI-LY-1, we confirm the complex formation between IP3R2 and Bcl-2 as a major determinant for cancer cell addiction to Bcl-2 at the ER.