The Use of ctDNA in the Diagnosis and Monitoring of Hepatocellular Carcinoma-Literature Review

Circulating tumor DNA and its role in detection, prognosis and therapeutics of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is considered the fifth most prevalent cancer among all types of cancers and has the third most morbidity value. It has the most frequent duplication time and a high recurrence rate. Recently, the most unique technique used is liquid biopsies, which carry many markers; the most prominent is circulating tumor DNA (ctDNA). Varied methods are used to investigate ctDNA, including various forms of polymerase chain reaction (PCR) [emulsion PCR (ePCR), digital PCR (dPCR), and bead, emulsion, amplification, magnetic (BEAMing) PCR]. Hence ctDNA is being recognized as a potential biomarker that permits early cancer detection, treatment monitoring, and predictive data on tumor burden are subjective to therapy or surgery. Numerous ctDNA biomarkers have been investigated based on their alterations such as 1) single nucleotide variations (either insertion or deletion of a nucleotide) markers including TP53, KRAS, and CCND1; 2) copy number variations which include markers such as CDK6, EFGR, MYC and BRAF; 3) DNA methylation (RASSF1A, SEPT9, KMT2C and CCNA2); 4) homozygous mutation includes ctDNA markers as CDKN2A, AXIN1; and 5) gain or loss of function of the genes, particularly for HCC. Various researchers have conducted many studies and gotten fruitful results. Still, there are some drawbacks to ctDNA namely low quantity, fragment heterogeneity, less stability, limited mutant copies and standards, and differential sensitivity. However, plenty of investigations demonstrate ctDNA's significance as a polyvalent biomarker for cancer and can be viewed as a future diagnostic, prognostic and therapeutic agent. This article overviews many conditions in genetic changes linked to the onset and development of HCC, such as dysregulated signaling pathways, somatic mutations, single-nucleotide polymorphisms, and genomic instability. Additionally, efforts are also made to develop treatments for HCC that are molecularly targeted and to unravel some of the genetic pathways that facilitate its early identification.

Methylated ctDNA Quantification: Noninvasive Approach to Monitoring Hepatocellular Carcinoma Burden

BACKGROUND

Noninvasive, precision monitoring of hepatocellular carcinoma (HCC) treatment efficacy would greatly facilitate personalized therapy and improve patient outcomes. We hypothesize that quantifying methylated circulating tumor DNA (ctDNA) can be used to effectively monitor HCC burden without the need for biopsy.

STUDY DESIGN

Blood samples were collected from 25 patients, 21 with HCC and 4 with benign liver masses, at various timepoints throughout the course of treatment at a high-volume academic medical center. Quantification of methylated ctDNA molecules assessed CpG sites on more than 550 preselected cancer-specific amplicons. The tumor methylation score (TMS) was calculated by measuring the difference between the amount of methylation in the plasma and buffy coat with a normal cutoff value of 120 or less.

RESULTS

Among 10 patients with surgical HCC (5 surgical resections and 5 liver transplants), TMS revealed a statistically significant, rapid postoperative decline in 9. One patient who had a persistently elevated TMS on postoperative day 1 was subsequently found to have had metastatic disease. Patients in the negative control cohort all had normal-range pre- and postoperative TMS. Preoperative TMS correlated moderately with tumor burden on pathology (Spearman r = 0.54) of surgical specimens. From 11 subjects undergoing systemic therapy or Y90 radioembolization, analysis of 16 time periods demonstrated that the change in TMS (ΔTMS) was better associated with tumor progression than the change in Δalpha-fetoprotein (area under the curve 0.800 and 0.783, respectively). A composite score combining ΔTMS and Δalpha-fetoprotein further improved performance for detecting tumor progression with an area under the curve of 0.892.

CONCLUSIONS

These findings indicate that ctDNA methylation scores can effectively evaluate changes in tumor burden without the need for tumor biopsy.

Circulating Tumor DNA Profiling in Liver Transplant for Hepatocellular Carcinoma, Cholangiocarcinoma, and Colorectal Liver Metastases: A Programmatic Proof of Concept

INTRODUCTION

Circulating tumor DNA (ctDNA) is emerging as a promising, non-invasive diagnostic and surveillance biomarker in solid organ malignancy. However, its utility before and after liver transplant (LT) for patients with primary and secondary liver cancers is still underexplored.

METHODS

Patients undergoing LT for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), and colorectal liver metastases (CRLM) with ctDNA testing were included. CtDNA testing was conducted pre-transplant, post-transplant, or both (sequential) from 11/2019 to 09/2023 using Guardant360, Guardant Reveal, and Guardant360 CDx.

RESULTS

21 patients with HCC (n = 9, 43%), CRLM (n = 8, 38%), CCA (n = 3, 14%), and mixed HCC/CCA (n = 1, 5%) were included in the study. The median follow-up time was 15 months (range: 1-124). The median time from pre-operative testing to surgery was 3 months (IQR: 1-4; range: 0-5), and from surgery to post-operative testing, it was 9 months (IQR: 2-22; range: 0.4-112). A total of 13 (62%) patients had pre-transplant testing, with 8 (62%) having ctDNA detected (ctDNA+) and 5 (32%) not having ctDNA detected (ctDNA-). A total of 18 (86%) patients had post-transplant testing, 11 (61%) of whom were ctDNA+ and 7 (33%) of whom were ctDNA-. The absolute recurrence rates were 50% (n = 5) in those who were ctDNA+ vs. 25% (n = 1) in those who were ctDNA- in the post-transplant setting, though this difference was not statistically significant (p = 0.367). Six (29%) patients (HCC = 3, CCA = 1, CRLM = 2) experienced recurrence with a median recurrence-free survival of 14 (IQR: 6-40) months. Four of these patients had positive post-transplant ctDNA collected following diagnosis of recurrence, while one patient had positive post-transplant ctDNA collected preceding recurrence. A total of 10 (48%) patients had sequential ctDNA testing, of whom n = 5 (50%) achieved ctDNA clearance (+/-). The remainder were ctDNA+/+ (n = 3, 30%), ctDNA-/- (n = 1, 10%), and ctDNA-/+ (n = 1, 11%). Three (30%) patients showed the acquisition of new genomic alterations following transplant, all without recurrence. Overall, the median tumor mutation burden (TMB) decreased from 1.23 mut/Mb pre-transplant to 0.00 mut/Mb post-transplant.

CONCLUSIONS

Patients with ctDNA positivity experienced recurrence at a higher rate than the ctDNA- patients, indicating the potential role of ctDNA in predicting recurrence after curative-intent transplant. Based on sequential testing, LT has the potential to clear ctDNA, demonstrating the capability of LT in the treatment of systemic disease. Transplant providers should be aware of the potential of donor-derived cell-free DNA and improved approaches are necessary to address such concerns.

Extracellular Vesicles as Liquid Biopsy Biomarkers across the Cancer Journey: From Early Detection to Recurrence

BACKGROUND

Cancer is a dynamic process and thus requires highly informative and reliable biomarkers to help guide patient care. Liquid-based biopsies have emerged as a clinical tool for tracking cancer dynamics. Extracellular vesicles (EVs), lipid bilayer delimited particles secreted by cells, are a new class of liquid-based biomarkers. EVs are rich in selectively sorted biomolecule cargos, which provide a spatiotemporal fingerprint of the cell of origin, including cancer cells.

CONTENT

This review summarizes the performance characteristics of EV-based biomarkers at different stages of cancer progression, from early malignancy to recurrence, while emphasizing their potential as diagnostic, prognostic, and screening biomarkers. We discuss the characteristics of effective biomarkers, consider challenges associated with the EV biomarker field, and report guidelines based on the biomarker discovery pipeline.

SUMMARY

Basic science and clinical trial studies have shown the potential of EVs as precision-based biomarkers for tracking cancer status, with promising applications for diagnosing disease, predicting response to therapy, and tracking disease burden. The multi-analyte cargos of EVs enhance the performance characteristics of biomarkers. Recent technological advances in ultrasensitive detection of EVs have shown promise with high specificity and sensitivity to differentiate early-cancer cases vs healthy individuals, potentially outperforming current gold-standard imaging-based cancer diagnosis. Ultimately, clinical translation will be dictated by how these new EV biomarker-based platforms perform in larger sample cohorts. Applying ultrasensitive, scalable, and reproducible EV detection platforms with better design considerations based upon the biomarker discovery pipeline should guide the field towards clinically useful liquid biopsy biomarkers.