Figure 2

Characterization of MYC dependence in human breast cancer cells. (A) Protein expression levels of MYC and phospho-MYC at T58 and S62 in a panel of 26 human breast cancer cell lines were analysed by Western blotting and quantitated by densitometry. The correlation between sensitivity to MYC siRNA (siMYC) and MYC protein expression level or MYC phosphorylation level was assessed. Sensitivity to MYC siRNA was determined by inhibition of BrdU incorporation after MYC depletion at 10 nM siRNA for each cell line in the panel and summarized in Additional file 1: Table S2. Higher numbers indicate higher sensitivity, i.e. sensitivity to MYC siRNA = 100% - relative BrdU incorporation. Sensitivity to MYC RNAi across ER- and ER + subtypes (B), and HER2- and HER2+ subtypes (C) were compared. R = Pearson correlation coefficient, P = the corresponding P-value.