Fc receptor-like B (FCRLB)

Fc receptor-like B (FCRLB) is a unique intracellular member of the Fc receptor-like (FCRL) family and is highly homologous to other FCRL proteins but lacks a transmembrane domain, confining it to a cytosolic function in B cells[1][3][4]. Its primary biological role involves maintaining balanced antibody production and fine-tuning humoral immunity, with knockout studies indicating that its absence leads to elevated antibody responses to T-dependent antigens[1][4]. FCRLB’s expression is notably upregulated in colorectal cancer, where it predicts poor prognosis and is associated with pathways such as extracellular matrix organization and cell adhesion[3][5]. Although little is known about its direct therapeutic targeting, FCRLB is increasingly regarded as a biomarker for cancer, particularly colorectal cancer[3][5]. It should be distinguished from other Fc receptor-like family members, many of which are surface-expressed receptors; FCRLB itself is intracellular but has functional relevance to immunity and disease.

Other names

FCRL2FCRLM2FCRYFREB2FREB-2FcRYFLJ31052FCRLYFc receptor homolog expressed in B-cells protein 2Fc receptor-like and mucin-like protein 2Fc receptor-like protein 2Fc receptor-related protein Y

None established for FCRLB-targeting drugs; theoretically would modulate antibody response or B cell function if targeted