We use a quantitative PCR-pyrosequencing assay to measure DNA methylation levels in three tumor-suppressor genes, i.e., CDKN2A, MLH1, and APC. We also use this methylation assay to study the long-interspersed nucleotide element (LINE-1) repetitive sequence that has high representation throughout the human genome. The gene discussed is MLH1; the disease is neoplasm.