DNMT1 and plasma cell myeloma: However, there is some evidence that a decrease in global DNA methylation has some anti-myeloma activity, particularly for therapy-resistant cells (Kiziltepe et al., 2007; Khong et al., 2008), and some studies developed biomarkers to estimate the sensitivity of primary myeloma cells for DNMT inhibitors (Moreaux et al., 2012).