The invention is related to a method of predicting the response to a treatment with a HER inhibitor in a patient comprising the steps of assessing a biomarker or a combination of biomarkers selected from the group consisting of amphiregulin, an epidermal growth factor, a transforming growth factor alpha, and a HER2 biomarker in a biological sample from the patient and predicting the response to the treatment with the HER inhibitor in the patient by evaluating the results of the first step. Further uses and methods wherein these markers are used are disclosed.