Methods and kits for detection of cancer-related mutations in a DNA sample using enzymatic restriction and real-time PCR. A DNA sample is subjected to digestion with a restriction endonuclease to obtain restriction endonuclease-treated DNA, followed by co-amplification of a restriction locus comprising a cancer mutation site and a control locus. A ratio of signal intensities of the amplification products of the restriction locus and the control locus is used to detect the cancer-related mutation.