SHOX2 gene methylation as a diagnostic marker of lung cancer

Purpose: In the actual study we have detected in the group of patients with mailgnant and also non-malignant disease the presence of DNA methylation of SHOX2 gene. The basic aim was to evaluate the reliability of detection of SHOX2 methylation in blood plasma as a potential alternative to used bronchial lavage. Further, we also determine the correlation of test results with samples of lavage and blood plasma. Materials and methods: The specimens were achieved of each patient from bronchial lavage and also peripheral blood and from january to december 2014 we analysed 69 parallel samples. DNA from bronchial lavage was purified with commercial kit Epi pro Lung BL DNA preparation kit (Epigenomics) and samples from peripheral blood using Epi pro Colon Plasma Quick kit (Epigenomics). Quantitative PCR analysis was accomplished using Epi pro Lung BL real-time PCR kit (Epigenomics) on the ABI 7500 Fast real-time PCR instrument (Life Technologies). Methylation results were performed with ΔΔCT method. Statistical characteristics of patients and other clinical data we analysed by methods of bi variant and descriptive statistics, like hood ratio by Cohen kappa and significance of observed differences by Maxwell and McNemar chi-quadrant test. Results: Altogether we analysed 69 parallel samples and methylation of SHOX2 gene was identified in 63,8% of samples. Overall the methylation was detected in 31 out of 37 lavage and 20 out of 31 blood samples. Diagnostic performance of the model with bio marker of SHOX2 methylation in lavage samples was determined at the level of 89,19% sensitivity and 84,62% specificity, on the other hand model with bio marker of SHOX2 methylation in plasma samples showed 80,65% sensitivity and 78,57% specificity. Conclusion: Generally, we established that methylation analysis of SHOX2 gene in bronchial lavage samples represents a reliable test, which may be used as an additional marker in the lung cancer diagnostics. Test of blood plasma features useful lternative test in the cases, when bronchoscopy is not possible. (author)