Over the last years, epigenetic changes, including DNA methylation and histone modifications detected in early tumorigenesis and cancer progression, have been proposed as biomarkers for cancer detection, tumor prognosis, and prediction to treatment response. Importantly for the clinical use of DNA methylation biomarkers, specific methylation signatures can be detected in many body fluids including serum/plasma samples. Several of these potential epigenetic biomarkers detected in women's cancers, colorectal cancers, prostate, pancreatic, gastric, and lung cancers are discussed. Studies conducted in breast cancer, for example, found that aberrant methylation detection of several genes in serum DNA and genome-wide epigenetic change could be used for early breast cancer diagnosis and prediction of breast cancer risk. In colorectal cancers, numerous studies have been conducted to identify specific methylation markers important for CRC detection and in fact clinical assays evaluating the methylation status of SEPT19 gene and vimentin, became commercially available. Furthermore, some epigenetic changes detected in gastric washes have been suggested as potential circulating noninvasive biomarkers for the early detection of gastric cancers. For the early detection of prostate cancer, few epigenetic markers have shown a better sensitivity and specificity than serum PSA, indicating that the inclusion of these markers together with current screening tools, could improve early diagnosis and may reduce unnecessary repeat biopsies. Similarly, in pancreatic cancers, abnormal DNA methylation of several genes including NPTX2, have been suggested as a diagnostic biomarker. Epigenetic dysregulation was also observed in several tumor suppressor genes and miRNAs in lung cancer patients, suggesting the important role of these changes in cancer initiation and progression. In conclusion, epigenetic changes detected in biological fluids could play an essential role in the early detection of several cancer types and this may have a great impact for the cancer precision medicine field.
Keywords: Colorectal cancers; Early epigenetic markers; Gastric and lung cancers; Genome-wide methylation; Pancreatic; Precision medicine; Prostate; Screening; Women’s cancers; miRNAs.