(2013) illustrated that Sitosterol treatment led to G1 arrest in human breast cancer MDA-MB-231 cells, corresponding to reduced levels of cyclin D1 and cyclin-dependent kinase (CDK) and increased levels of p21/Cip1 and p27/Kip1 proteins involved in inhibiting the kinase activity of CDK. Here, CCND1 is linked to breast carcinoma.