In MM, however, BH3 profiling [33,34] has revealed tumor-cell dependency on anti-apoptotic proteins to be highly heterogeneous, with primary MM cells at diagnosis being dependent on MCL-1 or BCL-2, or co-dependent on either BCL-2/MCL-1 or BCL-XL/MCL-1 [34]. The gene discussed is MCL1; the disease is neoplasm.