Predictive marker for egfr inhibitor treatment

An in vitro method of predicting the response of a cancer patient to treatment with an epidermal growth factor receptor (EGFR) inhibitor comprising:

• determining an expression level of a protein tyrosine phosphatase receptor type F (PTPRF) gene in a tumour sample of a cancer patient and comparing the expression level of the PTPRF gene in the tumor sample to a value representative of an expression level of the PTPRF gene in tumours of a population of patients deriving no clinical benefit form the treatment, wherein a higher expression level of the PTPRF gene in the tumour sample of the patient is indicative for patient who will derive clinical benefit from the treatment.