Epigenetic research in lung cancer diagnostics:
 A literature review

Abstract

Relevance: According to the International Agency for Research on Cancer (IARC), lung cancer (LC) currently ranks first in
 cancer incidence and mortality worldwide. The gold standard of LC diagnostics is the histological verification, the determination of the degree of invasion and tumor phenotype. At first glance, epigenetic methods seem to be secondary after determining the patient’s genetic profile. However, standard genetic analysis reveals only the DNA nucleotide sequence. Thus, epigenetic
 analysis is the only method that allows detecting potential abnormalities in cells. An important difference between genetic and
 epigenetic changes is that drugs are efficient against epigenetic changes but absolutely powerless against genetic mutations.
 The purpose of the study was to review and analyze the available molecular genetic methods for DNA methylation profiling in lung cancer.
 Results: All these observations support the hypothesis that methylation profiling in body fluids can help determine the people predisposed to or affected by LC. Circulating acellular DNA in the blood plasma contains tumor-specific mutations and disease-related DNA methylation patterns. Identifying new biomarkers-precursors of a potential cancer susceptibility or aggressiveness in such DNA would be a considerable advancement in prognostic medicine for patients at high risk of developing LC.
 Conclusion: A low level of LC detection might limit the number of DNA samples of patients with LC included in the studies.
 This is also the reason why specific methylation biomarkers have not yet been confirmed for clinical use. Future research on
 a larger number of blood samples, combined with the entire epigenome studies, may contribute to finding a group of LC biomarkers to improve LC detection.