Roche´s xCELLigence system is a facile, high content, and cell based kinase assay allowing for monitoring short term RTK activation and the long term biologic effect of the activation in real time in a single well. The advanced technology has improved in providing information on intracellular activity. The system is label-free, capable of monitoring cellular changes in real-time, and non-invasive. The technology does not need intensive optimization or special reagents such as peptides, antibodies, or probes. Also, it does not suffer from assay component interference.