Circulating tumor DNA: clinical roles in diffuse large B cell lymphoma

An Investigation into Cell-Free DNA in Different Common Cancers

Diagnosis is the most important step in different diseases, especially in cancers and blood malignancies. There are different methods in order to better diagnose of cancer, but many of them are invasive and also, some of them are not useful for immediate diagnosis. Cell-free DNA (cfDNA) or liquid biopsy easily accessible in peripheral blood is one of the non-invasive prognostic biomarkers in various areas of cancer management. In fact, amounts of cfDNA in serum or plasma can be used for diagnosis. In this review, we have considered some cancers such as hepatocellular carcinoma, lung cancer, breast cancer, and hematologic malignancies to compare the various methods of cfDNA diagnosis.

The Role of microRNA-155 as a Biomarker in Diffuse Large B-Cell Lymphoma

Diffuse Large B-cell Lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma (NHL). Despite the use of newer agents, such as polatuzumab vedotin, more than one-third of patients have ultimately relapsed or experienced refractory disease. MiRNAs are single-stranded, ~22-nucleotide-long RNAs that interact with their target RNA. They are significant regulators of post-transcriptional gene expression. One significant miRNA, miR-155, is involved in the pathophysiology of DLBCL and it is a critical modulator of hematopoiesis, inflammation, and immune responses. Targets of miR-155, such as histone deacetylase 4 (HDAC4), suppressor of cytokine signaling-1 (SOCS1) and immune cells, play a crucial role in DLBCL pathogenesis, since miR-155 regulates key pathways, transcription factors and cytokine expression and shapes the tumor microenvironment in DLBCL. In this review, we examine the role of miR-155 in DLBCL and its potential as a future diagnostic, prognostic, or predictive biomarker.

Early prognosis prediction in acute myeloid and acute lymphoid leukemia patients using cell-free DNA concentration ratios

Background: Cell-free DNA (cfDNA) is a promising biomarker for disease prediction in many cancers, including acute leukemia (acute myeloid leukemia [AML] and acute lymphoblastic leukemia [ALL]). This study investigated the role of cfDNA in predicting relapse or unfavorable outcomes in acute leukemia patients upon initial diagnosis. Methods: Paired peripheral blood samples of 25 patients with ALL and AML were compared at baseline and induction/follow-up and clinically correlated with clinicopathological and outcome variables according to the risk category. cfDNA was isolated using commercial cfDNA extraction kits. The probability of poor outcomes in high-risk groups and a cut-off value for risk stratification minimal residual disease (MRD) positivity and outcome prediction were derived. Results: Twenty-five patients diagnosed with AML and ALL were risk-stratified based on NCI risk stratification, and of these 25 patients, 4 patients were of standard risk (SR) and 1 patient was of intermediate risk (IR), while a majority of patients (80%) were of high risk (HR). Of these, four HR patients passed away. The ratio of cfDNA reduction at baseline and the end of induction was a strong predictor of poor outcomes in high-risk patients, regardless of the MRD status. A cfDNA ratio score of 2.6 or higher at diagnosis/remission predicted poor outcomes, with higher accuracy than conventional MRD detection by flow cytometry. Conclusion: A higher cfDNA ratio at diagnosis/remission or at baseline predicts poor outcomes in acute leukemia patients. This pilot study suggests that cfDNA ratio scoring may be a useful tool for predicting prognosis in acute leukemia patients, regardless of the MRD status.

Cell-free DNA for detection of clonal B cells in diffuse large B cell lymphoma by sequencing

INTRODUCTION

Diffuse large B cell lymphoma (DLBCL) is the most common lymphoma in the western world. It is highly heterogeneous with a variable clinical course, but curable with chemo-immunotherapy in up to 70% of all cases. The lymphoma presents in lymph nodes and/or extranodal lymphoid tissue, and the diagnosis is based on invasive procedures for histopathologic evaluation.

METHODS

In this technical study, we evaluated cell-free DNA (cfDNA) from blood plasma to detect clonal B cells in patients with DLBCL using rearranged immunoglobulin heavy chain gene as targets by next-generation sequencing. Clonal B cell sequences and frequencies were determined from blood plasma cfDNA and cellular DNA from matched excised lymphoma tissues and mononuclear cells isolated from diagnostic bone marrow and blood samples from 15 patients.

RESULTS

We showed that identical clonal rearrangements could be detected in blood plasma and excised lymphoma tissue and that plasma cfDNA was superior in detecting clonal rearrangements compared to blood or bone marrow-derived cellular DNA.

CONCLUSION

These findings consolidate the role of blood plasma as a reliable and easily accessible source for detecting neoplastic cells in DLBCL.

Clinical implications of circulating tumor DNA in predicting the outcome of diffuse large B cell lymphoma patients receiving first-line therapy

BACKGROUND

Circulating tumor DNA (ctDNA) has been proven to be a promising tumor-specific biomarker in solid tumors, but its clinical utility in risk stratification and early prediction of relapse for diffuse large B cell lymphoma (DLBCL) has not been well explored.

METHODS

Here, using a lymphoma-specific sequencing panel, we assessed the prognostic and predictive utilities of ctDNA measurements before, during, and after first-line therapy in 73 Chinese DLBCL patients.

RESULTS

The pretreatment ctDNA level serving as an independent prognostic factor for both progression-free survival (PFS, adjusted HR 2.47; p = 0.004) and overall survival (OS, adjusted HR 2.49; p = 0.011) was confirmed in our cohort. Furthermore, the patients classified as molecular responders who presented a larger decrease in ctDNA levels after the initial two treatment cycles had more favorable PFS (unreached vs. 6.25 months; HR 5.348; p = 0.0015) and OS (unreached vs. 25.87; HR 4.0; p = 0.028) than non-responders. In addition, interim ctDNA clearance may be an alternative noninvasive method of positron emission tomography and computed tomography (PET-CT) for predicting better PFS (HR 3.65; p = 0.0033) and OS (HR 3.536; p = 0.016). We also demonstrated that posttreatment ctDNA was a sensitive indicator for detecting minimal residual disease (MRD) in patients with a high risk of recurrence (HR 6.471; p = 0.014), who were otherwise claimed to achieve radiographic CR (complete remission).

CONCLUSIONS

CtDNA is a promising noninvasive tool for prognosis prediction, response assessment, and early relapse prediction of first-line treatment in DLBCL patients.

ctDNA Is Useful to Detect Mutations at Codon 641 of Exon 16 of EZH2, a Biomarker for Relapse in Patients with Diffuse Large B-Cell Lymphoma

Simple Summary

It is well known that epigenetic modifications and proteins involved in this process are important in the biogenesis of diffuse large B-cell lymphoma. In this sense, we decided to analyze the EZH2 mutations, which are frequent in this neoplasm, using ctDNA to demonstrate the utility of this tool for searching these mutations. The importance of the study of this gene is due to its role in the biogenesis of lymphomas and also because there are selective inhibitors targeting EZH2. This targeted therapy could be particularly effective in patients with activating mutations in EZH2, remarking the importance of its detection.

Abstract

(1) Background: The epigenetic regulator EZH2 is a subunit of the polycomb repressive complex 2 (PRC2), and methylates H3K27, resulting in transcriptional silencing. It has a critical role in lymphocyte differentiation within the lymph node. Therefore, mutations at this level are implicated in lymphomagenesis. In fact, the mutation at the Y641 amino acid in the EZH2 gene is mutated in up to 40% of B-cell lymphomas. (2) Methods: We compared the presence of exon 16 EZH2 mutations in tumor samples and ctDNA in a prospective trial. These mutations were determined by Sanger sequencing and ddPCR. (3) Results: One hundred and thirty-eight cases were included. Ninety-eight were germinal center, and twenty had EZH2 mutations. Mean follow-up (IQR 25–75) was 23 (7–42) months. The tumor samples were considered the standard of reference. Considering the results of the mutation in ctDNA by Sanger sequencing, the sensibility (Se) and specificity (Sp) were 52% and 99%, respectively. After adding the droplet digital PCR (ddPCR) analysis, the Se and Sp increased to 95% and 100%, respectively. After bivariate analysis, only the presence of double-hit lymphoma (p = 0.04) or EZH2 mutations were associated with relapse. The median Progression free survival (PFS) (95% interval confidence) was 27.7 (95% IC: 14–40) vs. 44.1 (95% IC: 40–47.6) months for the mutated vs. wild-type (wt) patients. (4) Conclusions: The ctDNA is useful for analyzing EZH2 mutations, which have an impact on PFS.

Cell-Free Total Nucleic Acid-Based Genotyping of Aggressive Lymphoma: Comprehensive Analysis of Gene Fusions and Nucleotide Variants by Next-Generation Sequencing

Simple Summary

This study aimed to simultaneously demonstrate pathogenic chromosomal translocations and point mutations from both tissue biopsy and peripheral blood (PB) liquid biopsy (LB) samples of aggressive lymphoma patients. Matched samples were analyzed by next-generation sequencing for the same 125 genes. Eight different gene fusions, including the classical BCL2, BCL6, and MYC genes were detected in the corresponding samples with generally good agreement. Besides, mutations of 29 commonly affected genes, such as BCL2, MYD88, NOTCH2, EZH2, and CD79B could be identified in the matched samples at a rate of 16/24 (66.7%). Our prospective study demonstrates a non-invasive approach to identify frequent gene fusions and variants in aggressive lymphomas. In conclusion, PB LB sampling substantially supports the oncogenetic diagnostics of lymphomas, especially at anatomically critical sites (such as the central nervous system).

Abstract

Chromosomal translocations and pathogenic nucleotide variants both gained special clinical importance in lymphoma diagnostics. Non-invasive genotyping from peripheral blood (PB) circulating free nucleic acid has been effectively used to demonstrate cancer-related nucleotide variants, while gene fusions were not covered in the past. Our prospective study aimed to isolate and quantify PB cell-free total nucleic acid (cfTNA) from patients diagnosed with aggressive lymphoma and to compare with tumor-derived RNA (tdRNA) from the tissue sample of the same patients for both gene fusion and nucleotide variant testing. Matched samples from 24 patients were analyzed by next-generation sequencing following anchored multiplexed polymerase chain reaction (AMP) for 125 gene regions. Eight different gene fusions, including the classical BCL2, BCL6, and MYC genes, were detected in the corresponding tissue biopsy and cfTNA specimens with generally good agreement. Synchronous BCL2 and MYC translocations in double-hit high-grade B-cell lymphomas were obvious from cfTNA. Besides, mutations of 29 commonly affected genes, such as BCL2, MYD88, NOTCH2, EZH2, and CD79B, could be identified in matched cfTNA, and previously described pathogenic variants were detected in 16/24 cases (66.7%). In 3/24 cases (12.5%), only the PB sample was informative. Our prospective study demonstrates a non-invasive approach to identify frequent gene fusions and variants in aggressive lymphomas. cfTNA was found to be a high-value representative reflecting the complexity of the lymphoma aberration landscape.

Liquid biopsy in extranodal NK/T-cell lymphoma: a prospective analysis of cell-free DNA genotyping and monitoring

Satisfactory tumor material is often hard to obtain for molecular analysis in extranodal natural killer (NK)/T-cell lymphoma (NKTCL) at present. However, the accuracy and utility of circulating cell-free DNA (cfDNA) genotyping have not been adequately assessed in NKTCL. We therefore performed targeted next-generation sequencing on tumor tissues and a series of longitudinal plasma samples prospectively collected from a cohort of high-risk NKTCL patients. Concordance of genotyping results of paired baseline tumor and cfDNA and the predictive value of dynamic cfDNA monitoring were evaluated. At baseline, 59 somatic variants in 31 genes were identified in tumor and/or plasma cfDNA among 19 out of 24 high-risk NKTCL patients (79.2%). Plasma cfDNA had a sensitivity of 72.4% for detection of somatic variants identified in tumor biopsies before treatment. Plasma cfDNA also allowed the identification of mutations that were undetectable in tumor biopsies. These results were also verified in a validation cohort of an additional 23 high-risk NKTCL patients. Furthermore, longitudinal analysis showed that patients with rapid clearance of NKTCL-related mutations from plasma had higher complete remission rates (80.0% vs 0%; P = .004) and more favorable survival (1-year progression-free survival [PFS] rate, 79.0% vs 20.0%; P = .002) compared with those with persisting or emerging mutations in plasma. In addition, low cfDNA concentration before treatment was associated with favorable survival outcome for patients with NKTCL (1-year PFS, 90.0% vs 36.4%; P = .012). In conclusion, cfDNA mirrors tumor biopsy for detection of genetic alterations in NKTCL and noninvasive dynamic plasma cfDNA monitoring might be a promising approach for tracking response and survival outcome for patients with NKTCL.

miR-210 and miR-152 as Biomarkers by Liquid Biopsy in Invasive Ductal Carcinoma

Detecting circulating microRNAs (miRNAs; miRs) by means of liquid biopsy is an important tool for the early diagnosis and prognosis of breast cancer (BC). We aimed to identify and validate miR-210 and miR-152 as non-invasive circulating biomarkers, for the diagnosis and staging of BC patients, confirming their involvement in tumor angiogenesis. Methods: RT-qPCR was performed and MiRNA expression analysis was obtained from plasma and fragments of BC and benign breast condition (BBC) women patients, plus healthy subjects. Additionally, the immunohistochemistry technique was carried out to analyze the expression of target proteins. Results: Tumor fragments showed increased expression of oncomiR-210 and decreased expression of miR-152 tumoral suppressor. Both miRNAs were increased in plasma samples from BC patients. The receiver operating characteristic (ROC) curve analysis revealed that only the expression of oncomiR-210 in tissue samples and only the expression of the miR-152 suppressor in plasma have the appropriate sensitivity and specificity for use as differential biomarkers between early/intermediate and advanced stages of BC patients. In addition, there was an increase in the expression of hypoxia-inducible factor 1-alpha (HIF-1α), insulin-like growth factor 1 receptor (IGF-1R), and vascular endothelial growth factor (VEGF) in BC patients. On the contrary, a decrease in Von Hippel–Lindau (VHL) protein expression was observed. Conclusions: This study showed that increased levels of miR-210 and decreased levels of miR152, in addition to the expressions of their target proteins, could indicate, respectively, the oncogenic and tumor suppressive role of these miRNAs in fragments. Both miRNAs are potential diagnostic biomarkers for BC by liquid biopsy. In addition, miR-152 proved to be a promising biomarker for disease staging.

Genotyping on ctDNA Identifies Shifts in Mutation Spectrum Between Newly Diagnosed and Relapse/Refractory DLBCL

Purpose

Diffuse large B cell lymphoma (DLBCL) is an aggressive B-cell malignancy with clinical and molecular heterogeneity whose genetics may have clinical implications for patient stratification and treatment. The circulating tumor DNA (ctDNA) is a novel noninvasive, real-time, and tumor-specific biomarker harboring tumor-derived genetic alterations that are identical to those of tumor cells, thus showing great promise in individualized medicine, including precise diagnosis, prediction of prognosis, response monitoring, and relapse detection for DLBCL.

Patients and Methods

In this study, we applied NGS analysis to tumor biopsies and ctDNA samples from 16 DLBCL subjects. Then, we compared the genomic alterations from 41 newly diagnosed patients and 56 relapsed/refractory (R/R) patients.

Results

Our results show that ctDNA can function as a liquid biopsy for tracking recurrently mutated genes in DLBCL (sensitivity: 87.50%). The mutational profiles of newly diagnosed and R/R DLBCL groups largely overlapped, but the frequencies of some gene mutations differ between the two cohorts. The distribution of mutations also revealed different frequencies in the two cohorts due to different signaling pathways. Genes from apoptosis pathway, immune response and BCR pathway suffered more mutations in R/R patients.

Conclusion

Overall, this study establishes ctDNA as an easily accessible source of tumor DNA for DLBCL genotyping and provides a deeper understanding of the somatic alteration spectrum for both newly diagnosed and R/R DLBCL patients.

The Impact of Pre-transplant Cell-free DNA Levels on Leukemia Relapse and Transplant-related Complications in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Background:

Cell-free DNA, which may be considered as “liquid” biopsy, may serve as a diagnostic and prognostic marker not only in hematological malignancies but in solid tumors as well.

Aims:

To investigate the prognostic role of pre-transplant cell-free DNA levels in allogeneic hematopoietic stem cell transplant recipients.

Study Design:

Retrospective cohort study.

Methods:

A total of 177 allogeneic hematopoietic stem cell transplant recipients [median age: 36 (16-66) years; male/female: 111/66] with an initial diagnosis of acute leukemia were included in the study. Cell-free DNA was extracted from pre-transplant serum samples by using the MagNA Pure Compact Nucleic Acid Isolation Kit I with the MagNA Pure Compact instrument (Roche Diagnostics, Penzberg, Germany).

Results:

A positive correlation was demonstrated between cell-free DNA and age (p=0.018; r=0.177). Pre-transplant cell-free DNA levels were lower in bcr-abl (+) patients (p=0.001), while an adverse correlation was indicated between cell-free DNA and bcr-abl levels (p=0.001; r=−0.531). Acute lymphoblastic leukemia patients with bcr-abl positivity (p=0.001) or abnormal cytogenetics (p=0.038) represented significantly lower pre-transplant cell-free DNA levels. Cell-free DNA levels were lower in patients who developed sinusoidal obstruction syndrome (p=0.035). In terms of long-term complications, acute myeloid leukemia patients who experienced post-transplant relapse had significantly lower pre-transplant cell-free DNA levels (p=0.024). Overall survival was not statistically different between high- and low- cell-free DNA groups (45.2% vs 22.5; p=0.821).

Conclusion:

In general, low serum levels of pre-transplant cell-free DNA seem to be associated with transplant-related morbidities and may be considered an adverse prognostic factor for allogeneic hematopoietic stem cell transplant recipients.

The role of cell free DNA and liquid biopsies in haematological conditions

Cell free nucleic acids (CFNAs) are nucleic acids released from cells that circulate within bodily fluids. Recent advances in molecular techniques have led the ability to interrogate CFNAs in a clinically meaningful way, for example the identification and assessment of foetal CFNAs in maternal blood, allowing minimally invasive testing for foetal genetic abnormalities. The majority of CFNAs arise from haemopoietic cells, making it a particularly rich source of genetic information in haematological conditions. Furthermore, the innate genetic heterogeneity of haematological malignancies, as epitomised by multiple myeloma, lend itself well to “liquid biopsies”. This approach promises to provide a more wholistic assessment of whole disease genetics, especially when contrasted against the current gold-standard of single site tissue biopsies. This review briefly summarises the definitions and physiology of CFNAs, both cell free DNA (cfDNA) and extracellular RNA (exRNA), before exploring the literature surrounding the current and future roles of cfDNA in the haematological malignancies and patient care.

Histological transformation in malignant lymphoma: a possible role of PET/CT and circulating tumor DNA as noninvasive diagnostic tools

Introduction: Transformation is a multi-step event wherein indolent lymphomas, such as follicular lymphomas, are converted into an aggressive subtype, such as diffuse large B-cell lymphoma. This process progresses not only through mutations in several of the causative genes, such as TP53, CDKN2A/B, or MYC, but also through epigenetic or micro-environmental changes. Excisional biopsy is recommended when transformation is clinically suspected.Areas covered: The authors summarized the current knowledge regarding the clinicopathological and molecular features of transformed lymphomas and discussed the relevance of re-biopsy in the diagnosis of transformation, comparing it with noninvasive diagnostic tools [fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) and circulating tumor DNA (ctDNA) analysis].Expert opinion: Pathological confirmation by biopsy is considered the golden standard for diagnosis and is indispensable for determining subsequent treatment strategies. The potential weakness of this approach is its invasiveness and the unavailability of pathological findings outside the biopsied areas. In the context of relapse, PET/CT is used mainly for the selection of the best suitable biopsy site, while ctDNA has the potential for detecting systemic genomic changes associated with relapse before clinical presentation. Future investigations should be focused on combining biopsies with new technologies for an early and accurate diagnosis of transformation.

A case of primary gastric diffuse large B-cell lymphoma occurring in chronic myeloid leukemia

Chronic myeloid leukemia (CML) and Non-Hodgkin Lymphoma (NHL) are two different origins of hematological malignancies, which rarely occur at the same time. Moreover, NHL secondary to CML is common in T cell lymphoma, while NHL of B cell origin is rare. Since 1999, only 22 cases with B cell lymphoma have been reported, of which 4 cases have diffuse large B-cell lymphoma (DLBCL). The lesions of DLBCL were in lymph node, liver, jejunum, and soft palate. To our knowledge, it has no report for the primary gastric DLBCL (PG-DLBCL) occurring in CML. Here we reported a 63-year-old man of chronic phase (CP) CML associated with PG-DLBCL. The patient was diagnosed with CML nearly eight years ago and was treated with imatinib and nilotinib successively. However, gastroscopy found malignant lesions in the patient’s stomach in March 2018, and the masses were diagnosed as PG-DLBCL. Subsequently, with the treatment of the RCOP + lenalidomide regimen chemotherapy for 3 cycles, the patient achieved nearly complete remission (CR).

The Emerging Role of Minimal Residual Disease Testing in Diffuse Large B-Cell Lymphoma

PURPOSE OF REVIEW

Diffuse large B cell lymphoma (DLBCL) is characterized by clinical heterogeneity that is not fully accounted for by pathologic features. Furthermore, real-time treatment modifications and detection of relapse are typically guided by radiographic imaging modalities which are imperfect. Here, we review the potential utility of minimal residual disease (MRD) assessment for informing treatment decisions and detecting relapse.

RECENT FINDINGS

The most promising method of MRD detection is based on analysis of circulating tumor DNA in the peripheral blood of patients with DLBCL. This approach can predict outcomes and response to treatment as well as detect relapse prior to clinical signs of recurrent disease. While some studies of MRD in DLBCL have been in the prospective setting, the ability of this technology to alter clinical outcomes is currently unknown. MRD detection provides a non-invasive way to gather information about DLBCL at various time points throughout the disease course. Its role is evolving and should be incorporated into prospective studies in order to demonstrate an impact on patient outcomes.