Since the approval of tPA derived from Chinese hamster ovary (CHO) cells in 1986, stable expression of recombinant proteins has become a very important system for the manufacture of therapeutic proteins. With an increasing number of therapeutic proteins in development, the demand for fast and robust development of manufacturing cell lines is still increasing. During the past 30 years, the productivity of stable recombinant cell lines could be increased from <100 mg/L to several g/L. The huge increase in productivity…