Background: Lung (LC), prostate (PCa) and colorectal (CRC) cancers are the most incident in males worldwide. Despite recent advances, optimal population-based cancer screening methods remain an unmet need. Due to its early onset, cancer specificity and accessibility in body fluids, aberrant DNA promoter methylation might be a valuable minimally invasive tool for early cancer detection. Herein, we aimed to develop a minimally invasive methylation-based test for simultaneous early detection of LC, PCa and CRC in males, using liquid biopsies.
Results: Circulating cell-free DNA was extracted from 102 LC, 121 PCa and 100 CRC patients and 136 asymptomatic donors' plasma samples. Sodium-bisulfite modification and whole-genome amplification was performed. Promoter methylation levels of APCme, FOXA1me, GSTP1me, HOXD3me, RARβ2me, RASSF1Ame, SEPT9me and SOX17me were assessed by multiplex quantitative methylation-specific PCR. SEPT9me and SOX17me were the only biomarkers shared by all three cancer types, although they detected CRC with limited sensitivity. A "PanCancer" panel (FOXA1me, RARβ2me and RASSF1Ame) detected LC and PCa with 64% sensitivity and 70% specificity, complemented with "CancerType" panel (GSTP1me and SOX17me) which discriminated between LC and PCa with 93% specificity, but with modest sensitivity. Moreover, a HOXD3me and RASSF1Ame panel discriminated small cell lung carcinoma from non-small cell lung carcinoma with 75% sensitivity, 88% specificity, 6.5 LR+ and 0.28 LR-. An APCme and RASSF1Ame panel independently predicted disease-specific mortality in LC patients.
Conclusions: We concluded that a DNA methylation-based test in liquid biopsies might enable minimally invasive screening of LC and PCa, improving patient compliance and reducing healthcare costs. Moreover, it might assist in LC subtyping and prognostication.
Keywords: Circulating cell free DNA; Colorectal cancer; DNA methylation; Epigenetic biomarkers; Liquid biopsy; Lung cancer; Prostate cancer.