As it appears that high nucleolin levels are associated with cancer development in ErbB2-positive breast cancer patients, and since anti-nucleolin RNAi and competitive inhibition of nucleolin by binding of GFP-TM-NLS peptides appeared to reduce ErbB2 activation, we hypothesized that treatment with nucleolin-targeting drugs could decrease breast cancer cell growth. This evidence concerns the gene ERBB2 and breast carcinoma.