Provided herein are methods for simultaneously determining the functional status of multiple signaling pathways in a diseased cell sample obtained from a subject to thereby select for therapeutic use in the subject a targeted therapeutic agent that affects the signaling pathway with the highest level of aberrant activity in the subject's cells. Also provided are methods for determining whether a signaling pathway is ultrasensitive in a diseased cell sample from a subject, also allowing for selection of an effective targeted therapeutic agent for therapeutic use in the subject. Methods of administering a selected targeted therapeutic agent to the subject are also provided. In particular, the treatment of human subjects diagnosed with cancer is disclsoed involving selecting therapeutics for the treatment of cancer by identifying in a culture of viable cancer cells in the presence of an activator of a signaling pathway, whether the targeted therapeutic affects this pathway by engendering an effect on cell adhesion or attachment.
