Threshold effect of CD79b cell-surface expression for in vitro efficacy and expression across lymphoma and leukemia. (A) CD79b-vcMMAE displays potent in vitro activity across NHL cell lines. and bars inidcate CD79b cell surface–negative and –positive cell lines, respectively. (B) Cell-surface expression is the primary predictor of response in vitro. (C) CD79b is broadly expressed across lymphomas and CLL. HCL indicates hairy cell leukemia; MZL, marginal zone lymphoma. (D) CD79b expression is maintained after relapse/progression from chemotherapy treatment in DLBCL (left panel) and FL (right panel). (E) CD79b expression is broadly expressed across DLBCL subtypes.