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result(s) for
"Chan, Stephen L"
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Lengthening and shortening of plasma DNA in hepatocellular carcinoma patients
by
Wong, Vincent Wai-Sun
,
Cheng, Suk Hang
,
Chan, Stephen L.
in
Base Pairing - genetics
,
Biological Sciences
,
Biopsy
2015
Significance We used massively parallel sequencing to study the size profiles of plasma DNA samples at single-base resolution and in a genome-wide manner. We used chromosome arm-level z -score analysis (CAZA) to identify tumor-derived plasma DNA for studying their specific size profiles. We showed that populations of aberrantly short and long DNA molecules existed in the plasma of patients with hepatocellular carcinoma. The short ones preferentially carried the tumor-associated copy number aberrations. We further showed that there were elevated amounts of mitochondrial DNA in the plasma of hepatocellular carcinoma patients. Such molecules were much shorter than the nuclear DNA in plasma. These findings have shed light on fundamental biological characteristics of plasma DNA and related diagnostic applications for cancer.
The analysis of tumor-derived circulating cell-free DNA opens up new possibilities for performing liquid biopsies for the assessment of solid tumors. Although its clinical potential has been increasingly recognized, many aspects of the biological characteristics of tumor-derived cell-free DNA remain unclear. With respect to the size profile of such plasma DNA molecules, a number of studies reported the finding of increased integrity of tumor-derived plasma DNA, whereas others found evidence to suggest that plasma DNA molecules released by tumors might be shorter. Here, we performed a detailed analysis of the size profiles of plasma DNA in 90 patients with hepatocellular carcinoma, 67 with chronic hepatitis B, 36 with hepatitis B-associated cirrhosis, and 32 healthy controls. We used massively parallel sequencing to achieve plasma DNA size measurement at single-base resolution and in a genome-wide manner. Tumor-derived plasma DNA molecules were further identified with the use of chromosome arm-level z -score analysis (CAZA), which facilitated the studying of their specific size profiles. We showed that populations of aberrantly short and long DNA molecules existed in the plasma of patients with hepatocellular carcinoma. The short ones preferentially carried the tumor-associated copy number aberrations. We further showed that there were elevated amounts of plasma mitochondrial DNA in the plasma of hepatocellular carcinoma patients. Such molecules were much shorter than the nuclear DNA in plasma. These results have improved our understanding of the size profile of tumor-derived circulating cell-free DNA and might further enhance our ability to use plasma DNA as a molecular diagnostic tool.
Journal Article
Plasma DNA tissue mapping by genome-wide methylation sequencing for noninvasive prenatal, cancer, and transplantation assessments
by
Chan, Stephen L.
,
Cheng, Suk Hang
,
Ng, Simon S. M.
in
Adult
,
Algorithms
,
B-Lymphocytes - metabolism
2015
Plasma consists of DNA released from multiple tissues within the body. Using genome-wide bisulfite sequencing of plasma DNA and deconvolution of the sequencing data with reference to methylation profiles of different tissues, we developed a general approach for studying the major tissue contributors to the circulating DNA pool. We tested this method in pregnant women, patients with hepatocellular carcinoma, and subjects following bone marrow and liver transplantation. In most subjects, white blood cells were the predominant contributors to the circulating DNA pool. The placental contributions in the plasma of pregnant women correlated with the proportional contributions as revealed by fetal-specific genetic markers. The graft-derived contributions to the plasma in the transplant recipients correlated with those determined using donor-specific genetic markers. Patients with hepatocellular carcinoma showed elevated plasma DNA contributions from the liver, which correlated with measurements made using tumor-associated copy number aberrations. In hepatocellular carcinoma patients and in pregnant women exhibiting copy number aberrations in plasma, comparison of methylation deconvolution results using genomic regions with different copy number status pinpointed the tissue type responsible for the aberrations. In a pregnant woman diagnosed as having follicular lymphoma during pregnancy, methylation deconvolution indicated a grossly elevated contribution from B cells into the plasma DNA pool and localized B cells as the origin of the copy number aberrations observed in plasma. This method may serve as a powerful tool for assessing a wide range of physiological and pathological conditions based on the identification of perturbed proportional contributions of different tissues into plasma.
Journal Article
Epigenetic analysis of cell-free DNA by fragmentomic profiling
2022
Cell-free DNA (cfDNA) fragmentation patterns contain important molecular information linked to tissues of origin. We explored the possibility of using fragmentation patterns to predict cytosine-phosphate-guanine (CpG) methylation of cfDNA, obviating the use of bisulfite treatment and associated risks of DNA degradation. This study investigated the cfDNA cleavage profile surrounding a CpG (i.e., within an 11-nucleotide [nt] window) to analyze cfDNA methylation. The cfDNA cleavage proportion across positions within the window appeared nonrandom and exhibited correlation with methylation status. The mean cleavage proportion was ∼twofold higher at the cytosine of methylated CpGs than unmethylated ones in healthy controls. In contrast, the mean cleavage proportion rapidly decreased at the 1-nt position immediately preceding methylated CpGs. Such differential cleavages resulted in a characteristic change in relative presentations of CGN and NCG motifs at 50 ends, where N represented any nucleotide. CGN/NCG motif ratios were correlated with methylation levels at tissue-specific methylated CpGs (e.g., placenta or liver) (Pearson’s absolute r > 0.86). cfDNA cleavage profiles were thus informative for cfDNA methylation and tissue-of-origin analyses. Using CG-containing end motifs, we achieved an area under a receiver operating characteristic curve (AUC) of 0.98 in differentiating patients with and without hepatocellular carcinoma and enhanced the positive predictive value of nasopharyngeal carcinoma screening (from 19.6 to 26.8%). Furthermore, we elucidated the feasibility of using cfDNA cleavage patterns to deduce CpG methylation at single CpG resolution using a deep learning algorithm and achieved an AUC of 0.93. FRAGmentomics-based Methylation Analysis (FRAGMA) presents many possibilities for noninvasive prenatal, cancer, and organ transplantation assessment.
Journal Article
Prognostic Nutritional Index (PNI) Predicts Tumor Recurrence of Very Early/Early Stage Hepatocellular Carcinoma After Surgical Resection
by
Chan, Stephen L.
,
Wong, Vincent W. S.
,
Chong, Charing C. N.
in
Blood Platelets - pathology
,
Carcinoma, Hepatocellular - diagnosis
,
Carcinoma, Hepatocellular - mortality
2015
Background
Approximately one-quarter of patients with Barcelona Clinic Liver Cancer (BCLC) stage 0/A hepatocellular carcinoma (HCC) suffer from tumor relapse within the first year after surgical resection. Little data is available for inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and prognostic nutritional index (PNI), in predicting the clinical outcome of patients with very early/early stage HCC who underwent curative surgery.
Methods
A retrospective cohort study of 324 patients with BCLC stage 0/A primary HCC undergoing surgical resection was conducted to investigate the prognostic impacts of NLR, PLR, and PNI.
Results
The low-PNI group (<45) had an adverse overall survival (1-year survival rate of 92 vs. 97 %; 5-year survival rate of 57 vs. 82 %;
p
< 0.001) and disease-free survival (1-year survival rate of 69 vs. 85 %; 5-year survival rate of 39 vs. 63 %;
p
< 0.001). It was an independent predictor for disease-specific death, and early and late tumor relapses, with hazard ratios of 2.78 (
p
< 0.001), 1.82 (
p
= 0.011), and 2.55 (
p
= 0.013), respectively. Neither NLR nor PLR had any prognostic significance.
Conclusions
The PNI is a significant prognostic factor for OS and DFS of patients with very early/early stage HCC receiving curative surgery.
Journal Article
Noninvasive detection of cancer-associated genome-wide hypomethylation and copy number aberrations by plasma DNA bisulfite sequencing
by
Hui, Edwin P.
,
Chan, Stephen L.
,
Ng, Simon S. M.
in
adverse effects
,
Algorithms
,
Biological Sciences
2013
We explored the detection of genome-wide hypomethylation in plasma using shotgun massively parallel bisulfite sequencing as a marker for cancer. Tumor-associated copy number aberrations (CNAs) could also be observed from the bisulfite DNA sequencing data. Hypomethylation and CNAs were detected in the plasma DNA of patients with hepatocellular carcinoma, breast cancer, lung cancer, nasopharyngeal cancer, smooth muscle sarcoma, and neuroendocrine tumor. For the detection of nonmetastatic cancer cases, plasma hypomethylation gave a sensitivity and specificity of 74% and 94%, respectively, when a mean of 93 million reads per case were obtained. Reducing the sequencing depth to 10 million reads per case was found to have no adverse effect on the sensitivity and specificity for cancer detection, giving respective figures of 68% and 94%. This characteristic thus indicates that analysis of plasma hypomethylation by this sequencing-based method may be a relatively cost-effective approach for cancer detection. We also demonstrated that plasma hypomethylation had utility for monitoring hepatocellular carcinoma patients following tumor resection and for detecting residual disease. Plasma hypomethylation can be combined with plasma CNA analysis for further enhancement of the detection sensitivity or specificity using different diagnostic algorithms. Using the detection of at least one type of aberration to define an abnormality, a sensitivity of 87% could be achieved with a specificity of 88%. These developments have thus expanded the applications of plasma DNA analysis for cancer detection and monitoring.
Journal Article
Cancer Genome Scanning in Plasma: Detection of Tumor-Associated Copy Number Aberrations, Single-Nucleotide Variants, and Tumoral Heterogeneity by Massively Parallel Sequencing
by
Liao, Gary JW
,
Lai, Paul BS
,
Lo, YMD
in
Biomarkers
,
Breast Neoplasms - blood
,
Breast Neoplasms - genetics
2013
Tumor-derived DNA can be found in the plasma of cancer patients. In this study, we explored the use of shotgun massively parallel sequencing (MPS) of plasma DNA from cancer patients to scan a cancer genome noninvasively.
Four hepatocellular carcinoma patients and a patient with synchronous breast and ovarian cancers were recruited. DNA was extracted from the tumor tissues, and the preoperative and postoperative plasma samples of these patients were analyzed with shotgun MPS.
We achieved the genomewide profiling of copy number aberrations and point mutations in the plasma of the cancer patients. By detecting and quantifying the genomewide aggregated allelic loss and point mutations, we determined the fractional concentrations of tumor-derived DNA in plasma and correlated these values with tumor size and surgical treatment. We also demonstrated the potential utility of this approach for the analysis of complex oncologic scenarios by studying the patient with 2 synchronous cancers. Through the use of multiregional sequencing of tumoral tissues and shotgun sequencing of plasma DNA, we have shown that plasma DNA sequencing is a valuable approach for studying tumoral heterogeneity.
Shotgun DNA sequencing of plasma is a potentially powerful tool for cancer detection, monitoring, and research.
Journal Article
Genome-wide detection of cytosine methylation by single molecule real-time sequencing
2021
5-Methylcytosine (5mC) is an important type of epigenetic modification. Bisulfite sequencing (BS-seq) has limitations, such as severe DNA degradation. Using single molecule real-time sequencing, we developed a methodology to directly examine 5mC. This approach holistically examined kinetic signals of a DNA polymerase (including interpulse duration and pulse width) and sequence context for every nucleotide within a measurement window, termed the holistic kinetic (HK) model. The measurement window of each analyzed double-stranded DNA molecule comprised 21 nucleotides with a cytosine in a CpG site in the center. We used amplified DNA (unmethylated) and M.SssI-treated DNA (methylated) (M.SssI being a CpG methyltransferase) to train a convolutional neural network. The area under the curve for differentiating methylation states using such samples was up to 0.97. The sensitivity and specificity for genome-wide 5mC detection at single-base resolution reached 90% and 94%, respectively. The HK model was then tested on human–mouse hybrid fragments in which each member of the hybrid had a different methylation status. The model was also tested on human genomic DNA molecules extracted from various biological samples, such as buffy coat, placental, and tumoral tissues. The overall methylation levels deduced by the HK model were well correlated with those by BS-seq (r = 0.99; P < 0.0001) and allowed the measurement of allele-specific methylation patterns in imprinted genes. Taken together, this methodology has provided a system for simultaneous genome-wide genetic and epigenetic analyses.
Journal Article
The evolving role of lenvatinib at the new era of first-line hepatocellular carcinoma treatment
2023
Emergence of multi-targeted kinase inhibitors (MTIs) and immune checkpoint inhibitors (ICI) have changed the landscape of management in hepatocellular carcinoma (HCC). Combination therapy involving ICI has superseded sorafenib as the first-line treatment option for advanced HCC due to their superior response rates and survival benefits based on recently published phase III trials. However, the role of first-line lenvatinib remains uncertain as no prospective trials have compared its efficacy with ICI in advanced HCC. Several retrospective studies have shown that first-line lenvatinib may not be inferior to ICI combination. Indeed, a growing body of evidence suggests that ICI treatment is associated with inferior treatment outcome in non-viral HCC patients, questioning the supremacy of ICI treatment in all patients and rendering first-line lenvatinib as a potential preferred treatment option. Furthermore, in high-burden intermediate-stage HCC, accumulating evidence supports first-line lenvatinib, or in combination with transarterial chemoembolization (TACE), as a preferred treatment option over TACE alone. In this Review, we describe the latest evidence surrounding the evolving role of first-line lenvatinib in HCC.
Journal Article
Long-term impact of liver function on curative therapy for hepatocellular carcinoma: application of the ALBI grade
by
Manas, Derek
,
Lai, Paul BS
,
Iñarrairaegui, Mercedes
in
631/67/1059
,
692/4028/67/1504/1610/4029
,
692/700/1750
2016
Background:
Application of curative therapy for hepatocellular carcinoma is crucially dependent on underlying liver function. Using the recently described ALBI grade we examined the long-term impact of liver dysfunction on survival of early-stage hepatocellular carcinoma (HCC) patients.
Methods:
This cohort study comprised 2559 HCC patients from different geographic regions, all treated with curative intent. We also examined the relation between indocyanine green (ICG) clearance and ALBI score. Survival was measured from the date of treatment to the date of death or last follow-up.
Results:
The ALBI score correlated well with ICG clearance. Among those undergoing surgical resection, patients with ALBI grade-1 (good liver function) survived approximately twice as long as those with ALBI grade-2 (less good liver function), although more than 90% of these patients were classified as Child–Pugh (C-P) grade A. In the cohort receiving ablative therapies, there was a similar difference in survival between ALBI grade-1 and grade-2. Cox regression analysis confirmed that the ALBI score along with age, gender, aetiology and tumour factors (AFP, tumour size/number and vascular invasion) independently influenced survival in HCC patients receiving curative treatments.
Conclusions:
The ALBI score represents a simple approach to the assessment of liver function in patients with HCC. After potentially curative therapy, those with ALBI grade-1 survived approximately twice as long as those with ALBI grade-2. These data suggest that ALBI grade-1 patients are appropriately treated with surgical resection whereas ALBI grade-2 patients may, where the option exists, be more suitable for liver transplantation or the less invasive curative ablative therapies.
Journal Article
Future perspectives on immunotherapy for hepatocellular carcinoma
2025
In recent years, several global phase III trials have shown that combinations of immune checkpoint inhibitors (ICIs) offer superior efficacy and survival compared to multi-kinase inhibitors, establishing them as the gold standard for treating patients with advanced hepatocellular carcinoma (HCC). This success has led to investigations into expanding the use of immunotherapy into various other settings and populations, including neoadjuvant and adjuvant therapies, patients with decompensated liver function and those awaiting liver transplantation. Despite its proven efficacy, a significant number of patients still develop resistance to immunotherapy, highlighting the need for innovative strategies to address this challenge. Approaches aimed at enhancing tumour immunogenicity, such as combining immunotherapy with transarterial chemoembolization or radiation therapies, show significant promise. Additionally, novel immunotherapeutics – such as triplet therapy, bispecific antibodies, adoptive T-cell therapy and cancer vaccines – are in early development for HCC. These agents have demonstrated potential for synergistic effects with existing ICIs, with initial studies yielding positive outcomes. In this review, we offer our future perspective on immunotherapy, emphasizing emerging indications, novel combination strategies and the development of new immunotherapeutic agents. Overall, the future of immunotherapy in HCC is brimming with extraordinary potential, set to transform the treatment landscape and redefine the possibilities for managing this challenging disease.
Journal Article