ERBB2 and triple-negative breast carcinoma: We have reported previously [21] that cambogin (chemical structure shown in Figure 1A) strongly inhibits cell proliferation in several breast cancer cell lines, including MCF-7 (ER+PR+HER2−), SK-BR-3 (ER−PR−HER2+) and MDA-MB-468 (ER−PR−HER2−, also known as TNBC (triple negative breast cancer)).