AFP and hepatocellular carcinoma: Several studies also indicated that the methylation status of some HCC‐related genes in HCC tissues was associated with abnormal serum AFP level.30, 31 Furthermore, this finding encouraged us to explore whether the methylation detection of DNAH17 gene in circulating tumor DNA (ctDNA) could be a sensitive biomarker for AFP‐negative HCC patients which would be useful for HCC early diagnosis.