Activated ERK causes activation of many kinds of genes, including cyclin D1, which results in malignant cell transformation (Wada and Penninger 2004). Blockage of the AKT or ERK signaling pathway results in programmed cell death and growth inhibition of tumor cells (Li et al. 2012; Degterev et al. 2003). In this study, we found that lupeol suppressed the phosphorylation of AKT and ERK in PCNA-1 cells