ERBB2 and breast cancer: In our study, Her2/neu-positive SK-BR3 cells (see http://www.merckmillipore.com/DE/de/product/fordocumentation, accessed on 30 July 2021) tolerated SSP concentrations in the higher nM range, at least for several days without significant signs of cell death, indicating a higher variability in SSP-sensitivity in different Her2/neu-positive human breast cancer cells.