Compositions and methods for determining an increased likelihood of a response to a targeted treatment of a cancer disease including isolating genomic DNA from a patient sample, amplifying a fragment of DNA by means of PCR with a specific pair of amplification primers, determining if the amplified fragment comprises a wildtype sequence or a mutation by means of a High Resolution Melting Analysis (HRM), and correlating the presence or absence of a mutation with an increased likelihood of success of said targeted treatment. Respective primer pairs, compositions and kits are also claimed.