For instance, aberrant DNA methylation of the mutL homolog 1 (MLH1) promoter can induce the inactivation of this gene, thus leading to a mismatch DNA repair (MMR) pathway disturbance in 20% of colorectal cancer and resulting in microsatellite instability (MSI) (Geissler et al. 2024). The gene discussed is MLH1; the disease is colorectal cancer.