The only study that evaluated cfDNA methylation profiling to monitor response in patients with anaplastic lymphoma kinase (ALK) rearrangements is that of Janke et al. The authors used a technique called cfMeDIP-seq (cell-free methylation DNA immunoprecipitation followed by high-throughput sequencing) to detect 5-mC signals, from blood plasma samples (n = 66) of 21 metastatic NSCLC lung adenocarcinoma patients treated with one or multiple lines of ALK-directed TKI therapy. Here, ALK is linked to non-small cell lung carcinoma.