This sample harbored multiple genomic alterations consistent with aggressive prostate cancer (determined by targeted cfDNA-seq in AR, MYC, NCOA2, RB1, TP53, NKX3-1, BRCA2, and PTEN; Supplementary Table S3), suggesting that dedifferentiation of aggressive mCRPC can be detected in cfDNA by 5hmC-seq. The gene discussed is RB1; the disease is prostate cancer.