CDK4 and neoplasm: We also confirmed that safranal treatment downregulated the protein expression levels of NF-κB p65, p-IκBα (Ser32), E2F1, Skp2, c-MYC, p-Rb (Ser807), CDK4, CDK6, and CDK2 and elevated p21 and p27 expression in safranal-treated tumor tissues compared with the vehicle control (Figures 6E,F), which is in agreement with the in vitro findings.