CD79B Gene: Function, Expression, and Mutations in B-Cell Malignancies

The CD79B gene encodes the Ig-beta protein, a crucial component of the B-cell antigen receptor (BCR) complex. CD79B, along with CD79A (Ig-alpha), forms a heterodimer that associates with membrane-bound immunoglobulin. This complex is essential for B-cell development, signaling, and survival. CD79B contains an immunoreceptor tyrosine-based activation motif (ITAM) that becomes phosphorylated upon antigen binding, initiating downstream signaling cascades. Mutations in CD79B are frequently observed in certain B-cell lymphomas, particularly diffuse large B-cell lymphoma (DLBCL), contributing to chronic active BCR signaling and tumor growth.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• B cell receptor signaling pathway (KEGG hsa04662)

• NF-kappa B signaling pathway (KEGG hsa04064)

• PI3K-Akt signaling pathway (KEGG hsa04151)

• MAPK signaling pathway (KEGG hsa04010)

CD79B (Ig-beta) is a transmembrane protein that forms a heterodimer with CD79A (Ig-alpha) to constitute the signaling component of the B-cell receptor (BCR). It contains an ITAM motif in its cytoplasmic tail, which is phosphorylated by Src-family kinases upon antigen binding, leading to recruitment of Syk and activation of downstream pathways such as NF-κB, PI3K, and MAPK. CD79B is essential for B-cell maturation and antibody production. In B-cell malignancies, mutations in the ITAM region (particularly at Y196) result in enhanced BCR signaling, promoting tumor cell survival and proliferation. CD79B is also a target for antibody-drug conjugates (e.g., polatuzumab vedotin) in DLBCL therapy.