From global untargeted workflows we were able to identify key proteins that are differentially regulated in CHO cells, which map onto existing understanding of CHO cell metabolism within bioreactors. High expression of proteins such as LAMP1 and GSTM7 during the CHO cell stress phase suggest that the drop in viable cell numbers (Figure ) may be driven by oxidative stress, in line with other studies. The entire quantitative proteomics discovery data sets provide a rich resource which could have further application, and while we select eight biomarkers, parallel reaction monitoring techniques on the latest available technology can push that number into the hundreds or even thousands of biomarkers on comparable time scales. As the protein targets are representative of the key cellular processes occurring during fed batch bioreactors a similar approach could be used to examine bioreactors under different run conditions, giving better information as to how the cells are responding to different growth conditions. For instance, within perfusion bioreactors, apoptotic resistant cells undergo several exponential growth phases , or providing data for dynamic self-driving bioreactor cultivation. Other potential applications would be in cell line development. During selection of stably transfected cells lines for the production of biotherapeutics, hundreds of cells may be automatically selected and grown into monoclonal colonies. Performing this targeted assay on both high and low producing clones may help identify biochemical reasons for this, aiding in the identification of gene targets for improving host cell productivity.