ERBB2 and neoplasm: In order to investigate HER2 effect on tumor development and gene expression, M13SV1R2N1 cells were cultured under similar condition as R2d cells, i.e. in MSU-1 medium [21] without growth factors/hormones except 5% FBS for more than 10 passages, (referred to as R2N1d) (Figure 1A).