CCND1 and cancer: Loss of cyclin D1 expression was also observed in several types of human cancer cells lines treated with α-glucosidase inhibitors, such as N-methyl-1-deoxynojirimycin (MDNJ) and N- [8-(3-ethynylphenoxy) octyl]-1-deoxynojirimycin [58], [59], or tunicamycin, the classical and the most used inhibitor of N-glycosylation [60], [61].