ERBB2 and cancer: This study assessed the ability of two highly cationic peptides, the synthetic 13-mer NLS peptide [CGYGPKKKRKVGG] from the simian virus 40 large-T antigen and the synthetic 16-mer TAT peptide [GRKKRRQRRRPPQGYG] from the HIV-1 TAT protein, to drive the 111In-anti-HER2 (trastuzumab) RIC into the cell nucleus of two HER2-expressing cancer cell lines, A-431CEA-luc (HER2+) and SK-OV-31B9 (HER2++).