Table 1.

Patterns of expression of B‐cell‐lymphoma‐2 family prosurvival proteins in selected B‐cell malignancies

B‐cell malignancy	Major prosurvival proteins expressed	Level of BCL2 expression	Variability	Comment on mechanism
CLL	BCL2 > MCL >> BCLxL12, 14	High	Some variability, but always high	BCL2: loss of repression by miRNA 15/1610; MCL1 & BCLxL induced by CD40 ligation and microenvironmental stimuli12, 15
Follicular lymphoma	BCL21; BCLxL16; MCL117, 18	High	Rare to not be expressed	t(14;18) leads to constitutive expression from IgH promotor1; CD40L stimulates BCLxL expression16; MCL1 in centroblasts17
Diffuse large B‐cell lymphoma	BCL2 or MCL118	High in GC type; low in many ABC type	High; where MYC‐driven MCL1 > BCL2	Varies: including gene amplification,19 t(14;18) in double‐hit lymphoma, consequence of MYC dysregulation20
MCL	BCL2 > MCL118, 21	High	Minor	Consequence of Cyclin D1 dysregulation22; MCL1 high in blastoid21
Myeloma	BCL2, MCL1, BCLxL13, 23	High, especially t(11;14)	Moderate	BCL2 consequence of Cyclin dysregulation24; MCL1 constitutively expressed by plasma cells25; BCLxL increased through microenvironmental stimulation13
ALL	BCL2, MCL1, BCLxL26, 27	Variable	Significant26	Appears to mimic expression pattern of precursor cell; patterned by oncogenic driver

ABC, activated B‐cell or origin subtype; ALL, acute lymphoblastic leukemia; BCL2, B‐cell‐lymphoma‐2; GC, germinal center cell of origin subtype; MCL, mantle cell lymphoma.