In a study by Nargi et al. [43], it was demonstrated in a range of colorectal cancer (CRC) cell lines that NAC differentially induced cell cycle arrest or apoptosis in CRC cells and identified CDK inhibitor p21(WAF1/Cip1), functional p53, Ras status and basal levels of reactive oxygen species (ROS) in CRC cells as important determinants of susceptibility to apoptosis. The gene discussed is CDKN1A; the disease is colorectal carcinoma.