ERBB2 and cancer: Antiproliferative activity SA-5-Dox-LP suggested that the liposome was specific for HER2-positive cancer cell lines with IC50 values in the lower micromolar range (0.1 μM for BT-474 and A549 and 0.35 μM in Calu-3), whereas for MCF-7 cell lines that do not overexpress HER2, IC50 was 2 μM.