Whole-genome informed circulating tumor DNA analysis by multiplex digital PCR for disease monitoring in B-cell lymphomas: a proof-of-concept study

IntroductionAnalyzing liquid biopsies for tumor-specific aberrations can facilitate detection of measurable residual disease (MRD) during treatment and at follow-up. In this study, we assessed the clinical potential of using whole-genome sequencing (WGS) of lymphomas at diagnosis to identify patient-specific structural (SVs) and single nucleotide variants (SNVs) to enable longitudinal, multi-targeted droplet digital PCR analysis (ddPCR) of cell-free DNA (cfDNA).MethodsIn 9 patients with B-cell lymphoma (diffuse large B-cell lymphoma and follicular lymphoma), comprehensive genomic profiling at diagnosis was performed by 30X WGS of paired tumor and normal specimens. Patient-specific multiplex ddPCR (m-ddPCR) assays were designed for simultaneous detection of multiple SNVs, indels and/or SVs, with a detection sensitivity of 0.0025% for SV assays and 0.02% for SNVs/indel assays. M-ddPCR was applied to analyze cfDNA isolated from serially collected plasma at clinically critical timepoints during primary and/or relapse treatment and at follow-up.ResultsA total of 164 SNVs/indels were identified by WGS including 30 variants known to be functionally relevant in lymphoma pathogenesis. The most frequently mutated genes included KMT2D, PIM1, SOCS1 and BCL2. WGS analysis further identified recurrent SVs including t(14;18)(q32;q21) (IGH::BCL2), and t(6;14)(p25;q32) (IGH::IRF4). Plasma analysis at diagnosis showed positive circulating tumor DNA (ctDNA) levels in 88% of patients and the ctDNA burden correlated with baseline clinical parameters (LDH and sedimentation rate, p-value <0.01). While clearance of ctDNA levels after primary treatment cycle 1 was observed in 3/6 patients, all patients analyzed at final evaluation of primary treatment showed negative ctDNA, hence correlating with PET-CT imaging. One patient with positive ctDNA at interim also displayed detectable ctDNA (average variant allele frequency (VAF) 6.9%) in the follow-up plasma sample collected 2 years after final evaluation of primary treatment and 25 weeks before clinical manifestation of relapse.ConclusionIn summary, we demonstrate that multi-targeted cfDNA analysis, using a combination of SNVs/indels and SVs candidates identified by WGS analysis, provides a sensitive tool for MRD monitoring and can detect lymphoma relapse earlier than clinical manifestation

Different prognostic impact of recurrent gene mutations in chronic lymphocytic leukemia depending on IGHV gene somatic hypermutation status: a study by ERIC in HARMONY

Recent evidence suggests that the prognostic impact of gene mutations in patients with chronic lymphocytic leukemia (CLL) may differ depending on the immunoglobulin heavy variable (IGHV) gene somatic hypermutation (SHM) status. In this study, we assessed the impact of nine recurrently mutated genes (BIRC3, EGR2, MYD88, NFKBIE, NOTCH1, POT1, SF3B1, TP53, and XPO1) in pre-treatment samples from 4580 patients with CLL, using time-to-first-treatment (TTFT) as the primary end-point in relation to IGHV gene SHM status. Mutations were detected in 1588 (34.7%) patients at frequencies ranging from 2.3-9.8% with mutations in NOTCH1 being the most frequent. In both univariate and multivariate analyses, mutations in all genes except MYD88 were associated with a significantly shorter TTFT. In multivariate analysis of Binet stage A patients, performed separately for IGHV-mutated (M-CLL) and unmutated CLL (U-CLL), a different spectrum of gene alterations independently predicted short TTFT within the two subgroups. While SF3B1 and XPO1 mutations were independent prognostic variables in both U-CLL and M-CLL, TP53, BIRC3 and EGR2 aberrations were significant predictors only in U-CLL, and NOTCH1 and NFKBIE only in M-CLL. Our findings underscore the need for a compartmentalized approach to identify high-risk patients, particularly among M-CLL patients, with potential implications for stratified management

The potential of liquid biopsy for detection of the KIAA1549-BRAF fusion in circulating tumor DNA from children with pilocytic astrocytoma

Background Low-grade gliomas (LGGs) represent children’s most prevalent central nervous system tumor, necessitating molecular profiling to diagnose and determine the most suitable treatment. Developing highly sensitive screening techniques for liquid biopsy samples is particularly beneficial, as it enables the early detection and molecular characterization of tumors with minimally invasive samples. Methods We examined CSF and plasma samples from patients with pilocytic astrocytoma (PA) using custom multiplexed droplet digital polymerase chain reaction (ddPCR) assays based on whole genome sequencing data. These assays included a screening test to analyze BRAF duplication and a targeted assay for the detection of patient-specific KIAA1549::BRAF fusion junction sequences or single nucleotide variants. Results Our findings revealed that 5 out of 13 individual cerebrospinal fluid (CSF) samples tested positive for circulating tumor DNA (ctDNA). Among these cases, 3 exhibited the KIAA1549::BRAF fusion, which was detected through copy number variation (CNV) analysis (n = 1) or a fusion-specific probe (n = 2), while 1 case each displayed the BRAF V600E mutation and the FGFR1 N577K mutation. Additionally, a quantitative analysis of cell-free DNA (cfDNA) concentrations in PA CSF samples showed that most cases had low cfDNA levels, below the limit of detection of our assay (<1.9 ng). Conclusions While CNV analysis of CSF samples from LGGs still has some limitations, it has the potential to serve as a valuable complementary tool. Furthermore, it can also be multiplexed with other aberrations, for example, to the BRAF V600 test, to provide important insights into the molecular characteristics of LGGs

Simultaneous Ultra-Sensitive Detection of Structural and Single Nucleotide Variants Using Multiplex Droplet Digital PCR in Liquid Biopsies from Children with Medulloblastoma

Medulloblastoma is a malignant embryonal tumor of the central nervous system (CNS) that mainly affects infants and children. Prognosis is highly variable, and molecular biomarkers for measurable residual disease (MRD) detection are lacking. Analysis of cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) using broad genomic approaches, such as low-coverage whole-genome sequencing, has shown promising prognostic value. However, more sensitive methods are needed for MRD analysis. Here, we show the technical feasibility of capturing medulloblastoma-associated structural variants and point mutations simultaneously in cfDNA using multiplexed droplet digital PCR (ddPCR). Assay sensitivity was assessed with a dilution series of tumor in normal genomic DNA, and the limit of detection was below 100 pg of input DNA for all assays. False positive rates were zero for structural variant assays. Liquid biopsies (CSF and plasma, n = 47) were analyzed from 12 children with medulloblastoma, all with negative CSF cytology. MRD was detected in 75% (9/12) of patients overall. In CSF samples taken before or within 21 days of surgery, MRD was detected in 88% (7/8) of patients with localized disease and in one patient with the metastasized disease. Our results suggest that this approach could expand the utility of ddPCR and complement broader analyses of cfDNA for MRD detection

Human papillomavirus (HPV) load is higher in HPVDNA/p16 positive than in HPVDNA positive/p16 negative oropharyngeal squamous cell carcinoma but does not differ significantly between various subsites or correlate to survival

Objective Patients with human papillomavirus DNA positive (HPVDNA+) and p16ink4a overexpressing (p16+) oropharyngeal squamous cell carcinoma (OPSCC), especially those with cancer in the tonsillar and base of tongue subsites as compared to other OPSCC subsites have a better outcome than those with only HPVDNA+ or only p16+ cancer. Likewise having a high viral load has been suggested to be a positive prognostic factor. We therefore hypothesized, that HPV viral load could vary depending on OPSCC subsite, as well as with regard to whether the cancer was HPVDNA+ and p16+, or only HPVDNA+, or only p16+ and that this affected outcome. Material and methods To address these issues HPV viral load was determined by HPV digital droplet (dd) PCR in tumor biopsies with previously known HPVDNA/p16 status from 270 OPSCC patients diagnosed 2000–2016 in Stockholm, Sweden. More specifically, of these patients 235 had HPVDNA+/p16+, 10 had HPVDNA+/p16-, 13 had HPVDNA-/p16+ and 12 had HPVDNA-/p16- cancer. Results We found that HPVDNA+/p16+ OPSCC had a significantly higher viral load than HPVDNA+/p16- OPSCC. Moreover, there was a tendency for a higher viral load in the tonsillar and base of tongue OPSCC subsites compared to the other subsites and for a low viral load to correlate to a better clinical outcome but none of these tendencies reached statistical significance. Conclusion To conclude, the mean viral load in HPVDNA+/p16+ OPSCC was higher than in HPVDNA+/p16- OPSCC, but there was no statistically significant difference in viral load depending on OPSCC subsite or on clinical outcome

Different Prognostic Impact of Recurrent Gene Mutations in IGHV-Mutated and IGHV-Unmutated Chronic Lymphocytic Leukemia: A Retrospective, Multi-Center Cohort Study By Eric, the European Research Initiative on CLL, in Harmony

Abstract The mutational status of the immunoglobuin heavy variable (IGHV) genes is an undisputable strong prognostic factor that subdivides patients with chronic lymphocytic leukemia (CLL) into 2 subgroups, i.e. IGHV-unmutated CLL (U-CLL) and IGHV-mutated CLL (M-CLL). U-CLL and M-CLL have distinct landscapes of genomic aberrations as well as distinct prognosis, since U-CLL is considerably more aggressive than M-CLL. That said, there is considerable clinical heterogeneity among M-CLL patients, ranging from patients without need of treatment to patients requiring early therapeutic intervention, indicating the need to further refine prognosis in this subgroup. In recent years, it has become evident that the prognostic impact of genomic aberrations may differ depending on IGHV gene mutational status. Hence, defining genomic aberrations with prognostic impact in M-CLL patients may help identifying patients with an predicted unfavorable prognosis within this subgroup, with obvious implications for management of follow up and therapy choice. To study the clinical impact of recurrent gene mutations in relation to IGHV gene mutational status, we collected a large, multi-center cohort including 4,674 patients with CLL [median age at diagnosis, 64.5 years; male/female, n=2,962 (63%)/n=1,712 (37%); Binet stage A (n=3,369, 74%), B (n=827, 18%), and C (n=387, 8%); IGHV-mutated (M-CLL, n=2,498, 56%) and IGHV-unmutated (U-CLL, n=1,927, 44%); isolated del(13q) (n=1,868, 41%), trisomy 12 (n=571, 13%), del(11q) (n=503, 11%), and del(17p) (n=249, 5.5%); treated (n=2,745, 59%) and untreated (n=1,929, 41%)] and performed next-generation sequencing (NGS) and/or Sanger sequencing of 9 genes (BIRC3, EGR2, NFKBIE, MYD88, NOTCH1, POT1, SF3B1, TP53, and XPO1) on pre-treatment samples. Overall, pathogenic mutations in any of these genes were detected in 1720/4674 patients (36.8%, using a variant allele frequency cutoff of 5% for NGS), while the remaining patients were wildtype; 2 mutations were observed in 361 patients (7.7%) and 3 or more mutations in 58 patients (1.2%). The mutation frequency for the individual genes was: TP53 (10.4%, including TP53 mutations and/or del(17p)), NOTCH1 (10.1%, 3'UTR mutations not included), SF3B1 (9.3%), XPO1 (3.9%), POT1 (3.8%), NFKBIE (3.7%), BIRC3 (3.0%), EGR2 (2.5%) and MYD88 (2.5%; Figure 1A). Except for MYD88, gene mutations in each of the investigated genes were associated with significantly shorter time-to-first-treatment (TTFT) in univariate analysis. In multivariate analysis of Binet stage A patients (n=3,369; including all genes, IGHV gene mutational status, age at diagnosis and gender), SF3B1 (Hazard Ratio (HR) 1.79; p<0.001) , BIRC3 mutations (HR 1.50; p=0.004), XPO1 (HR 1.29; p=0.020), EGR2 (HR 1.42; p=0.021) and TP53 aberrations (HR 1.21; p=0.028), along with unmutated IGHV genes (HR 4.21; p<0.001) and male gender (HR 1.12; p=0.027) remained as independent factors for shorter TTFT. In a multivariate model focusing on M-CLL Binet stage A patients (n=2,049), SF3B1 (HR 2.72; p<0.001), NOTCH1 (HR 1.65; p=0.006), XPO1 (HR 2.21; p=0.021) and NFKBIE mutations (HR 1.74; p=0.025) were independent markers of poor TTFT (Figure 1B), while conversely in U-CLL Binet stage A cases (n=1157), SF3B1 mutations (HR 1.49; p<0.001), TP53 aberrations (HR 1.30; p=0.011), BIRC3 mutations (HR 1.49; p=0.016) and male gender (HR 1.20; p=0.012) were significant factors for shorter TTFT (Figure 1C). In summary, different spectra of genetic mutations independently predicted short TTFT in M-CLL and U-CLL, respectively, with SF3B1 mutations as the only aberration found to be significant predictor of shorter time to first treatment in both subgroups. Importantly, mutations within several genes (i.e. SF3B1, NOTCH1, XPO1 and NFKBIE) identified patients in the M-CLL subgroup with a high-risk profile; conversely, TP53 mutations did not affect TTFT in this subgroup. On these grounds, we suggest to include analysis of recurrent gene mutations to identify high-risk patients within the M-CLL subgroup. Figure 1 Figure 1. Disclosures Brieghel: AstraZeneca: Consultancy. Rossi: Janssen: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Verastem: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Cellestia: Honoraria, Research Funding. Scarfo: Astra Zeneca: Honoraria; Abbvie: Honoraria; Janssen: Honoraria, Other: Travel grants. Mattsson: Gilead: Research Funding. Baliakas: Janssen: Honoraria; Gilead: Honoraria, Research Funding; Abbvie: Honoraria. Martinez-Lopez: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. de la Serna: AbbVie, AstraZeneca, Beigene, Gilead, GSK, Janssen, Jazzpharma, Novartis, Roche: Consultancy; ABBVIE, ASTRAZENECA,ROCHE: Research Funding; AbbVie, AstraZeneca, Roche: Speakers Bureau. Hernández Rivas: Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Smedby: Jansen-Cilag: Other: part of a research collaboration between Karolinska Institutet and Janssen Pharmaceutica NV for which Karolinska Institutet has received grant support. Bullinger: Pfizer: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Gilead: Consultancy; Daiichi Sankyo: Consultancy, Honoraria; Hexal: Consultancy; Janssen: Consultancy, Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; Menarini: Consultancy; Novartis: Consultancy, Honoraria; Amgen: Honoraria; Astellas: Honoraria; Sanofi: Honoraria; Seattle Genetics: Honoraria; Bayer: Research Funding. Bosch: TAKEDA: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel. Terol: BMS: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Consultancy; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Hospital Clinico Valencia: Current Employment. Cuneo: AstraZeneca: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau. Gaidano: Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Niemann: Novo Nordisk Foundation: Research Funding; CSL Behring, Genmab, Takeda, Octapharma: Consultancy; Abbvie, AstraZeneca, Janssen: Consultancy, Research Funding. Ghia: Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Sunesis: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; ArQule/MSD: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Celgene/Juno/BMS: Consultancy, Honoraria; Gilead: Consultancy, Research Funding. Rosenquist: Roche: Honoraria; Janssen: Honoraria; Illumina: Honoraria; AstraZeneca: Honoraria; Abbvie: Honoraria

Different prognostic impact of recurrent gene mutations in chronic lymphocytic leukemia depending on IGHV gene somatic hypermutation status: a study by ERIC in HARMONY

International audienceRecent evidence suggests that the prognostic impact of gene mutations in patients with chronic lymphocytic leukemia (CLL) may differ depending on the immunoglobulin heavy variable (IGHV) gene somatic hypermutation (SHM) status. In this study, we assessed the impact of nine recurrently mutated genes ( BIRC3 , EGR2 , MYD88, NFKBIE , NOTCH1 , POT1 , SF3B1, TP53 , and XPO1 ) in pre-treatment samples from 4580 patients with CLL, using time-to-first-treatment (TTFT) as the primary end-point in relation to IGHV gene SHM status. Mutations were detected in 1588 (34.7%) patients at frequencies ranging from 2.3–9.8% with mutations in NOTCH1 being the most frequent. In both univariate and multivariate analyses, mutations in all genes except MYD88 were associated with a significantly shorter TTFT. In multivariate analysis of Binet stage A patients, performed separately for IGHV-mutated (M-CLL) and unmutated CLL (U-CLL), a different spectrum of gene alterations independently predicted short TTFT within the two subgroups. While SF3B1 and XPO1 mutations were independent prognostic variables in both U-CLL and M-CLL, TP53 , BIRC3 and EGR2 aberrations were significant predictors only in U-CLL, and NOTCH1 and NFKBIE only in M-CLL. Our findings underscore the need for a compartmentalized approach to identify high-risk patients, particularly among M-CLL patients, with potential implications for stratified management