CCND1 and colorectal cancer: In contrast, in another study by Bardon et al. [15], it was observed that in human colorectal cancer, POH reduced cyclin D1, cyclin-dependent kinases CDK4, and CDK2 but resulted in an increase in cyclin E. Rajesh and Howard [42] reported an increase in the G2/M phase of the cell cycle and elevated cyclin D1 expression in human prostate carcinoma following POH treatment.