“…Recently, many discoveries of non-protein serum markers have been documented-eg, mutated DNAs, methylated DNAs, RNAs (Keller et al, 2011;Rabman et al, 2011;Sehramm et al, 2011), which were regarded as potential tool for non-invasive lung cancer diagnosis and significantly improved diagnostic accuracy for lung cancer. However, protein markers measurable in serum are the most applicable for clinical routine assessments and large-scale population studies (Locker et al, 2006), because generally such tests are non-invasive, require less than 100 μL serum, have low dependence on operator expertise and special equipments, are low cost, have high reproducibility, and samples need no pretreatment (eg, extraction, purification or reverse transcription).…”