Furthermore, lopinavir has been shown to induce strong ER stress not via proteasome inhibition, but rather via reactive oxygen species-dependent Mitogen-Activated Protein Kinase 8 (JNK) activation [42] and has been previously described to induce ER stress in breast cancer cells, either triple-negative or non-triple-negative [43, 44]. This evidence concerns the gene MAPK8 and breast carcinoma.