Life expectancy rises steeply when a tumor is diagnosed at an early stage. Therefore, diagnosing cancer before it turns into an aggressive, barely curable disease is one of the main goals of oncological research in the 21st century. This is of vital importance for certain types of cancer for which survival rates drastically drop as primary tumors are detected by currently available screening procedures. Aberrant DNA methylation is a common hallmark of human cancer. This epigenetic mark is altered in instructive ways in the distinct stages of multistep tumorigenesis from the early onset of malignant transformation. Therefore, the possibility of detecting precise methylation signatures associated with particular cancers and the development of methodologies increasingly sensitive at detecting them, makes DNA methylation biomarkers attractive predictors for the development of effective diagnostic tests for the early detection of human neoplasia.