Kits and methods for diagnosing lung cancer

A method for measuring methylation ratio of DNA present in a plasma sample from a human subject suspected of having lung cancer, the method comprising:

• (a) subjecting DNA from a plasma sample obtained from the subject to digestion with at least one methylation-sensitive restriction endonuclease, thereby obtaining restriction endonuclease-treated DNA;
• (b) co-amplifying from the restriction endonuclease-treated DNA at least one restriction locus having increased methylation in lung cancer DNA compared to normal non-cancerous DNA and a control locus, wherein the at least one restriction locus is selected from the group consisting of SEQ ID NO:
• 1, SEQ ID NO:
• 2, SEQ ID NO:
• 3, SEQ ID NO:
• 4, SEQ ID NO:
• 5, and SEQ ID NO:
• 6, and wherein the control locus is a locus in the restriction endonuclease-treated DNA that is not cut by the methylation-sensitive restriction enzyme used in the digestion step, thereby generating at least one restriction locus amplification product, and a control locus amplification product;
• (c) determining a signal intensity for each generated restriction locus amplification product, wherein the signal intensity is indicative of a methylation level of CpG sites within the corresponding restriction locus, and determining a signal intensity for the control locus amplification product;
• and
• (d) calculating a ratio between the signal intensities of the amplification products of each of said at least one restriction locus and the control locus, thereby measuring methylation ratio of DNA in the plasma sample.