Used in targeted cancer therapy, particularly for treating B-cell malignancies such as diffuse large B-cell lymphoma (DLBCL). It functions by binding specifically to the CD79b protein on the surface of B-cells, enabling selective delivery of cytotoxic agents directly into cancerous cells when conjugated to a drug like monomethyl auristatin E (MMAE). This targeted approach minimizes damage to healthy tissues and enhances treatment efficacy. It is a key component in antibody-drug conjugates (ADCs) and has shown clinical benefit in combination with other therapies like rituximab and chemotherapy regimens.