EGFR and lung cancer: The practicality of this approach was demonstrated on the quantitative measurement of drug-resistant and sensitive lung cancer cell lines; this motif-targeting approach differentiates drug resistance-associated changes in phosphorylation stoichiometry from those at the protein as well as messenger RNA (mRNA) levels in lung cancer cells, which also suggested potential druggable target proteins in the EGFR- and CK2-centred kinase–substrate network.