In these studies, treatment of HER2/neu–overexpressing SKBR-3-LP breast cancer cells with scFv23–TNFα led to a 5- to 7-fold increase in TNFαreceptor-1 (TNFR1) expression, downregulation of Akt phosphorylation, and subsequent activation of the apoptotic cascade through caspase-8 and caspase-3 cleavage. Here, TNF is linked to breast carcinoma.