ERBB2 and breast cancer: This work focuses on the development of BC spheroids for TNBC (MDA-MB-231 and BT-20, which lack common target receptors and differ in proliferation and metastization capability) and HER2+ (BT-474, which expresses growth receptors and presents a high proliferative rate, as well as a relatively high rate of cell loss) cell subtypes highly applied in preclinical studies with chemotherapeutic agents [42].