ERBB2 and breast carcinoma: We next investigated the potential autophagy-modulating effect of TNP nanoparticles in the triple-negative (ER-, PR-, HER2-) murine mammary carcinoma cell line 4T1, which was known to be a difficult-to-treat cancer, and multidrug-resistant human breast carcinoma cell line MCF7/MDR, which showed minimal death after treatment with 20 μM doxorubicin for 24 h (Supplementary Fig 9).