ERBB2 and breast cancer: Three different receptor subtypes of breast cancer (BT-474 – Her2 + /ER + /PR + , MCF-7 – ER + /PR + , and MDA-MB-231 – TNBC) were incubated with 100 μM HS-27 for 15-minutes, washed thoroughly with PBS to remove unbound HS-27, and imaged with a confocal microscope.