ERBB2 and cancer: The development of targeted toxins based on non-immunoglobulin targetingmolecules appears to be one of the most advanced approaches in the targetedtherapy of malignant tumors with a high expression of the HER2 receptor.Earlier, we showed that the targeted toxin DARPin-PE40 consisting of theHER2-specific non-immunoglobulin polypeptide (the targeting module) and afragment of Pseudomonas exotoxin A (the toxic module) exhibitsan antitumor effect in vivo against the HER2-positiveadenocarcinoma xenograft.