AFP and hepatocellular carcinoma: Cai et al. [29] established a 32-genes-based 5hmC diagnostic model using circulating cell-free DNA and exhibited a great performance for distinguishing early-stage HCC from non-HCC (training set: area under curve (AUC) = 0.92, 95% confidence interval (CI): 0.91–0.94; validation set: AUC = 0.88, 95%CI: 0.86–0.91), which appeared to outperform α-fetoprotein (AFP) when detecting an early HCC and may compensate for the plight of those patients with early HCC misdiagnosed due to AFP.