ERBB2 and breast cancer: For instance, antibody‐directed targeting against HER2 did not increase tumor accumulation of small unilamellar immunoliposomes, as both targeted and non‐targeted liposomes achieved similarly high concentrations in HER2‐overexpressing breast cancer xenografts, being 7–8% injected dose per gram tumor tissue.[164] Another example where no difference in tumor uptake was found between anti‐HER2 targeted immunoliposomes and non‐targeted liposomes, being 1.9% and 1.7% at the end of treatment, respectively, was reported by Rodallec and coworkers.[165] Roveri et al.