Puromycin (RPL8), an old antibiotic derived from Streptomyces alboniger [46], is known that its antitumor activity is achieved by inhibiting 45S pre-ribosomal RNA and upstream binding factor (UBF) in MDA-MB-231 cells [47,48].It also has been found to induce apoptosis in breast cancer cells by insulin-like growth factor 1 (IGF-I), because it prevents the ribosomal protein generate process by causing the premature release of a polypeptide from the ribosome in malignant cells. The gene discussed is IGF1; the disease is breast cancer.