UQCRC2 and breast carcinoma: In the context of cancer progression, it was shown that ubiquinol–cytochromec reductase core protein II (UQCR2), an important subunit of complex III, is upregulated in human tumours, including lung adenocarcinoma and breast cancer.45 Interestingly, UQCR2 negatively regulates p53 levels by inducing its degradation through the interaction with PHB, a p53 chaperone.