In summary, we evaluated the influences of Leptin and SAHA on cell viability, cell cycle, and apoptosis in breast cancer cell lines, determined the mRNA and protein expressions of molecules associated with cell cycle and apoptosis, and identified the acetylated levels of AcH3 and AcH4 residues binding with p21WAF1/CIP1 promoter. Here, LEP is linked to breast carcinoma.