The present invention relates to a method for diagnosis of a cancer, comprising the steps of (i) determining the level of antibodies against epidermal growth factor receptor (EGFR) in a sample from a subject to be diagnosed, (ii) comparing the determined level in the sample to a control level derived from subjects without cancer； wherein a decreased level in the sample from the subject to be diagnosed as compared to the control level is indicative for cancer in the subject. Furthermore, the invention relates to method of predicting response and outcome of a treatment of a cancer with an inhibitor of EGFR activity.
