The present qPCR-based method successfully established CYP copy number alterations in lung adenocarcinoma samples, and the present study was the first that reasonably assumed an association between CYP multiplication in tumours and the disease outcome of paclitaxel-treated patients; namely, multiplication of CYP2C8 and/or CYP3A4 copy numbers was observed more frequently in non-responder patients (progression of disease/exit group) than in responders with complete remission of the disease. The gene discussed is CYP3A4; the disease is neoplasm.