CYCS and skin squamous cell carcinoma: Many biochemical processes, such as a loss of mitochondrial membrane potential, release of cytochrome C into the cytoplasm, expression of Bcl-2 family and caspase family proteins, and cleavage of poly ADP ribose polymerase, induced apoptosis in the skin squamous cell carcinoma A431 cell line after treatment with BBR (Wartenberg et al., 2003).