A method for predicting the responsiveness of a cancer cell to an MEK inhibitor, comprising detecting the presence of at least one mutation in one or more genes selected from the group consisting of ADAM12, COL14A1, TNN, and TP53, in the cancer cell, by contacting a nucleic acid sample derived from the cancer cell with at least one oligonucleotide which allows specific detection of the mutation wherein presence of mutation in ADAM12, COL14A1, TNN, TP53 and/or any combination thereof is indicative of decreased responsiveness of the cancer cell to the ERK inhibitor.