ZNF154 and cancer: Most cfDNA in blood comes from circulating white blood cells32; thus, we tested the hypothesis that ZNF154 methylation levels are not meaningfully elevated with age or sex by analyzing methylation at probe cg21790626 in TCGA Illumina 450 K methylation microarray data from 2711 circulating white blood cell samples (i.e., whole peripheral blood cell samples) from individuals without cancer.