Value Of Circulating Cell-free DNA As Diagnostic And Prognosis Tools For Hepatocellular Carcinoma

Background:The circulation tumor DNA (ctDNA) can provide a global landscape of the genetic profile of one patient’s tumor. These kinds of cell-free DNA (cfDNA) have some specific characterization, and reflect the progression, heterogeneity and invasiveness of tumor indirectly. The analysis of these rare DNA of cancerous origin shed into blood will represent a powerful and noninvasive liquid biopsy for the diagnosis of neoplastic disease, drug-sensitivity identification, prognosis evaluation and dynamic monitoring of treatment, as well as offering the opportunity to systematically track genomic evolution. Although some of insufficient are presented, qualitative and quantitative analyses of ctDNA have made it possible to identify both genetic and epigenetic aberrations at present. However, more technological advances, such as next-generation sequencing, have overcome some of restrictions and increased the throughput necessary for detection of abnormalities in tumor-linked ctDNA and will open up a broad range of clinical applications. This study was the first to synthesize these published results and evaluate the use of circulating cfDNA values for HCC diagnosis, and was also the first to apply a high-throughput sequencing platform to detect tumor-associated mutations in HCC from circulating tumor-derived DNA (ctDNA) and to evaluate the potential clinical value of this approach.Methods and Experimental Design:In meta-analysis, all articles that met our inclusion criteria were assessed using QUADAS guidelines after the literature research. We also investigated three subgroups in this meta-analysis:qualitative analysis of abnormal concentrations of circulating cfDNA; qualitative analysis of single-gene methylation alterations; and multiple analyses combined with alpha-fetoprotein (AFP). Statistical analyses were performed using the software Stata 12.0. We synthesized these published results and calculated accuracy measures (pooled sensitivity and specificity, positive/negative likelihood ratios [PLRs/NLRs], diagnostic odds ratios [DORs], and corresponding 95%confidence intervals [95%Cls]). Data were pooled using bivariate generalized linear mixed model. Furthermore, summary receiver operating characteristic curves (SROCs) and area under the curve (AUC) were used to summarize overall test performance. Heterogeneity and publication bias were also examined. Otherwise, in article research, using the MiSeqTM system, plasma and matched tumor DNA samples were analyzed for hotspot mutations in the TERT, CTNNB1, and TP53 genes that had been verified as the most prevalent mutations in HCC. We compared tumor and plasma data and prospectively investigated the association between significant mutations detected in ctDNA and the patients’clinical outcomes.Results:In meta-analysis, a total of 2424 subjects included 1280 HCC patients in 22 studies were recruited in this meta-analysis. Pooled sensitivity and specificity, PLR, NLR, DOR, AUC and CIs of quantitative analysis were 0.741 (95%CI:0.610-0.840),0.851 (95%CI:0.718-0.927),4.970 (95%CI:2.694-9.169),0.304 (95%CI:0.205-0.451),16.347 (95%CI:8.250-32.388) and 0.86 (95%CI:0.83-0.89), respectively. For qualitative analysis, the values were 0.538 (95%CI:0.401-0.669),0.944 (95%CI:0.889-0.972),9.545 (95%CI:5.298-17.196), 0.490 (95% CI:0.372-0.646),19.491 (95%CI:10.458-36.329) and 0.87 (95%CI:0.84-0.90), respectively. After combining with AFP assay, the values were 0.818 (95%CI:0.676-0.906), 0.960 (95%CI:0.873-0.988),20.195 (95%CI:5.973-68.282),0.190 (95%CI:0.100-0.359), 106.270 (95%CI:22.317-506.055) and 0.96 (95%CI:0.94-0.97), respectively.Otherwise, in article research, In 41 patients, we detected tumor-associated mutations for HCC in 8 (19.5%) plasma samples. Among them, one showed a tumor-associated mutation in ctDNA but not in the tumor tissue which we used to detect. We also found that ctDNA with mutations could be detected more easily in patients who suffered vascular invasion (P=0.041) and predicted a shorter recurrence-free survival time (P<0.001).There was no relationship between detectable mutations and concentration of cfDNA (P=0.884).Conclusion:The results in this meta-analysis suggest that circulating cfDNA have potential value for HCC diagnosis. However, it would not be recommended for using independently, which is based on the non-robust results. After combining with AFP, the diagnostic performance will be improved. Otherwise, we also found that the next sequencing technology could solve this bottleneck and provide a feasibility approach for circulating cfDNA detection. The results of our study suggest that tumor-associated mutations detected in plasma are associated with vascular invasion and might be used to predict clinical outcome for HCC patients. This kind of biomarker can overcome the limitations of tumor heterogeneity. Moreover, the diagnostic performance is improved if multiple mutations in different genes are combined. Further investigation with more data is needed.