Furthermore, as an illustrative example of the potential utility of methylation-based liquid biopsy in disease monitoring and treatment response assessment (16), we observed that during the 12-month follow-up, concurrent methylation profiling, and assessment of prolactin levels in the blood indicated that methylation markers clustered with nontumor specimens (Figure 2B-C), coinciding with normalization of prolactinemia levels, implying successful tumor control after surgery. The gene discussed is PRL; the disease is neoplasm.