Over the past decade, the scale of the biopharmaceutical market has grown due to the improvement of development and production processes. Also, the emergence of new biopharmaceuticals and biosimilars is accelerating the development of the production cell line. Among the various mammalian cells used for the production of biopharmaceuticals, Chinese Hamster Ovary (CHO) cell is in the spotlight occupying more than 60% because it possesses various advantages in terms of safety and bioprocess. For instance, the post-translational modification (PTM) processes of CHO cell are similar to humans so that it has little immunogenicity in the case that it was injected into humans. In addition, an adaptation of CHO cell in serum-free media and production on a large-scale is easier than the other cell lines relatively. In spite of these advantages, the cell line development using mammalian cells has some difficulties; not only it requires enormous time and labor, but also recombinant cell lines made by development processes have shown instabilities of gene expression. Therefore, our laboratory desires to accelerate market growth by solving these problems with cell engineering and process engineering.