ERBB2 and breast cancer: Given the challenges and limited options for treating triple-negativebreast cancer (TNBC) and HER2+ breast cancer, we evaluated the effectsof (±)-phaeocaulisin A (3), 21, and 50 on a panel of TNBC or HER2+ breast cancer cell lines: MDA-MB-468(TNBC), SKBR3 (HER2+), and MDA-MB-231 (TNBC).