SKP2 and cancer: In addition, CAPE treatment caused G1 or G2 cell cycle arrest in several cancer cells (Figure 2) through suppression of protein level of cyclin B1 [73,83], cyclin D1 [70,84,85], cyclin E [85], c-Myc [70,84], S-phase kinase-associated protein 2 (Skp2) [70], phospho-Rb [70,85], and β-catenin [86,87].