A study performed in 2008 found that, when a nanogel containing trastuzumab, an FDA-approved drug for treating HER2-positive breast cancer, was administered to a cell line containing HER2-overexpressing tumor cells, significant toxicity was observed, but, when administered to a cell line with normal HER2 expression, no toxic effect was observed [82]. This evidence concerns the gene ERBB2 and breast cancer.