Matalka et al. demonstrated that GHK, at 1 to 10 nanomolar, reactivated the apoptosis system, as measured by caspases 3 and 7, and inhibited the growth of human SH-SY5Y neuroblastoma cells, human U937 histiocytic lymphoma cells, and human breast cancer cells [9]. The gene discussed is CASP3; the disease is breast carcinoma.