Our study of qPCR and western blots show that solanine administration can significantly downregulate the expression of Cyclin D1/E1, CDK 4 and 6, upregulate P21, indicating that solanine affects the G1/S transition signal, blocks the progress of G1/S transition, inhibits cell growth of cancer cell and tumor growth in vivo. Here, CCND1 is linked to cancer.