A method of identifying a therapeutic compound for treating cancer in a human subject, the method including: providing a device that measures cell-substrate impedance; culturing cancer cells in the at least two wells, wherein the cancer cells are obtained from a human subject and have a receptor tyrosine kinase (RTK) pathway; adding to a first well a proposed therapeutic compound that affects an RTK pathway and an RTK stimulating factor for the RTK pathway to form a test well, and adding to another well the RTK stimulating factor to form a control well; continuously monitoring cell-substrate impedance of the at least two wells; and determining a difference in impedance or optionally in cell index between the test well and control well; and if significantly different, concluding the proposed therapeutic compound is therapeutically active in the RTK pathway within the cancer cells of the human subject.