In chronic lymphocytic leukemia,
mutations and deletion of chromosome 17p are well-characterized biomarkers associated with poor progression-free and overall survival following chemoimmunotherapy. ...Patients harboring low burden
mutations with variant allele frequencies of 0.3-15% have been shown to have similar dismal outcome as those with high burden mutations. We here describe a highly sensitive deep targeted next-generation sequencing assay allowing for the detection of
mutations as low as 0.2% variant allele frequency. Within a consecutive, single center cohort of 290 newly diagnosed patients with chronic lymphocytic leukemia, deletion of chromosome 17p was the only
aberration significantly associated with shorter overall survival and treatment-free survival. We were unable to demonstrate any impact of
mutations, whether high burden (variant allele frequency >10%) or low burden (variant allele frequency ≤10%), in the absence of deletion of chromosome 17p. In addition, the impact of high burden
aberration (deletion of chromosome 17p and/or
mutation with variant allele frequency >10%) was only evident for patients with IGHV unmutated status; no impact of
aberrations on outcome was seen for patients with IGHV mutated status. In 61 patients at time of treatment, the prognostic impact of
mutations over 1% variant allele frequency could be confirmed. This study furthers the identification of a clinical significant limit of detection for robust
mutation analysis in chronic lymphocytic leukemia. Multicenter studies are needed for validation of ultra-sensitive
mutation assays in order to define and implement a technical as well as a clinical lower limit of detection.
Landscape of somatic copy number alterations, mutations, and fusions in selected genes in newly diagnosed glioblastoma patients. The most frequent aberrations occurred in PTEN, CDKN2A/B, EGFR, RB1, ...and NPAS3, and the most frequent mutations were in PTEN, TP53, NF1, RB1, and EGFR. One NTRK2 fusion and three FGFR3‐TACC3 fusions were identified.
Glioblastoma (GBM) is an incurable brain tumor for which new treatment strategies are urgently needed. Next‐generation sequencing of GBM has most often been performed retrospectively and on archival tissue from both diagnostic and relapse surgeries with limited knowledge of clinical information, including treatment given. We sought to investigate the genomic composition prospectively in treatment‐naïve patients, searched for possible targetable aberrations, and investigated for prognostic and/or predictive factors. A total of 108 newly diagnosed GBM patients were included. Clinical information, progression‐free survival, and overall survival (OS) were noted. Tissues were analyzed by whole‐exome sequencing, single nucleotide polymorphism (SNP) and transcriptome arrays, and RNA sequencing; assessed for mutations, fusions, tumor mutational burden (TMB), and chromosomal instability (CI); and classified into GBM subgroups. Each genomic report was discussed at a multidisciplinary tumor board meeting to evaluate for matching trials. From 111 consecutive patients, 97.3% accepted inclusion in this study. Eighty‐six (77%) were treated with radiation therapy/temozolomide (TMZ) and adjuvant TMZ. One NTRK2 and three FGFR3‐TACC3 fusions were identified. Copy number alterations in GRB2 and SMYD4 were significantly correlated with worse median OS together with known clinical variables like age, performance status, steroid dose, and O6‐methyl‐guanine‐DNA‐methyl‐transferase status. Patients with CI‐median or TMB‐high had significantly worse median OS compared to CI‐low/high or TMB‐low/median. In conclusion, performing genomic profiling at diagnosis enables evaluation of genomic‐driven therapy at the first progression. Furthermore, TMB‐high or CI‐median patients had worse median OS, which can support the possibility of offering experimental treatment already at the first line for this group.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We evaluated longitudinal tracking of BRAF V600E in circulating cell-free DNA (cfDNA) as a marker of treatment response to BRAF inhibitor (BRAFi) combination therapies in non-melanoma solid tumors ...included in the Copenhagen Prospective Personalized Oncology (CoPPO) program.
Patients with BRAF V600E-mutated tumors were treated with combination therapies including BRAFi. Quantification of mutant cfDNA from plasma was determined and correlated to clinical outcomes. Exome sequencing was performed to identify possible resistance mutations.
Twenty-three patients had BRAF-mutated tumors out of 455 patients included in CoPPO and 17 started BRAFi combination (EGFRi/MEKi) therapy. Tumor responses were achieved in 8 out of 16 evaluable patients and the median overall- and progression-free survival (OS and PFS) was 15 and 4.8 months, respectively. Longitudinal measurements of BRAF V600E-mutant cfDNA indicated disease progression prior to radiological evaluation and a reduction in the mutant fraction of more than 50% after 4 and 12 weeks of therapy was associated with a significantly longer PFS (p=0.003 and p=0.029) and OS (p=0.029 and p=0.017). Furthermore, the baseline mutant fraction and total level of cfDNA positively correlated with tumor burden (p=0.026 and p=0.024). Finally, analysis of cfDNA at progression revealed novel mutations potentially affecting the MAPK pathway.
BRAFi combination therapies showed a response rate of 50% in BRAF V600E-mutated non-melanoma tumors. The fraction of BRAF-mutant cfDNA represent a sensitive indicator for clinical outcomes with plasma collected at week 4 and 12 as crucial time points for monitoring response and disease progression.
Genetic testing of BRCA1/2 includes screening for single nucleotide variants and small insertions/deletions and for larger copy number variations (CNVs), primarily by Sanger sequencing and multiplex ...ligation-dependent probe amplification (MLPA). With the advent of next-generation sequencing (NGS), it has become feasible to provide CNV information and sequence data using a single platform. We report the use of NGS gene panel sequencing on the Illumina MiSeq platform and JSI SeqPilot SeqNext software to call germline CNVs in BRCA1 and BRCA2. For validation 18 different BRCA1/BRCA2 CNVs previously identified by MLPA in 48 Danish breast and/or ovarian cancer families were analyzed. Moreover, 120 patient samples previously determined as negative for BRCA1/BRCA2 CNVs by MLPA were included in the analysis. Comparison of the NGS data with the data from MLPA revealed that the sensitivity was 100%, whereas the specificity was 95%. Taken together, this study validates a one-step bioinformatics work-flow to call germline BRCA1/2 CNVs using data obtained by NGS of a breast cancer gene panel. The work-flow represents a robust and easy-to-use method for full BRCA1/2 screening, which can be easily implemented in routine diagnostic testing and adapted to genes other than BRCA1/2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pediatric cancers are often difficult to classify and can be complex to treat. To ensure precise diagnostics and identify relevant treatment targets, we implemented comprehensive molecular profiling ...of consecutive pediatric patients with cancer relapse. We evaluated the clinical impact of extensive molecular profiling by assessing the frequency of identified biological onco-drivers, altered diagnosis, and/or identification of new relevant targeted therapies.
Forty-six tumor samples (44 fresh-frozen; two formalin-fixed paraffin embedded), two bone marrow aspirates, three cerebrospinal fluid samples, and one archived DNA were obtained from 48 children (0-17 years; median 9.5) with relapsed or refractory cancer, where the disease was rapidly progressing in spite of their current treatment or they had exhausted all treatment options. The samples were analyzed by whole-exome sequencing (WES), RNA sequencing (RNAseq), transcriptome arrays, and SNP arrays. Final reports were available within 3-4 weeks after patient inclusion and included mutation status, a description of copy number alterations, differentially expressed genes, and gene fusions, as well as suggestions for targeted treatment.
Of the 48 patients, 33 had actionable findings. The most efficient method for the identification of actionable findings was WES (39%), followed by SNP array (37%). Of note, gene fusions were identified by RNAseq in 21% of the samples. Eleven findings led to clinical intervention, i.e., oncogenetic counseling, targeted treatment, and treatment based on changed diagnosis. Four patients received compassionate use targeted therapy. Six patients experienced direct benefits in the form of stable disease or response.
The application of comprehensive genetic diagnostics in children with recurrent cancers allowed for discovery and implementation of effective targeted therapies and hereby improvement of outcome in some patients.
Genetic testing of BRCA1/2 includes screening for single nucleotide variants and small insertions/deletions and for larger copy number variations (CNVs), primarily by Sanger sequencing and multiplex ...ligation-dependent probe amplification (MLPA). With the advent of next-generation sequencing (NGS), it has become feasible to provide CNV information and sequence data using a single platform. We report the use of NGS gene panel sequencing on the Illumina MiSeq platform and JSI SeqPilot SeqNext software to call germline CNVs in BRCA1 and BRCA2. For validation 18 different BRCA1/BRCA2 CNVs previously identified by MLPA in 48 Danish breast and/or ovarian cancer families were analyzed. Moreover, 120 patient samples previously determined as negative for BRCA1/BRCA2 CNVs by MLPA were included in the analysis. Comparison of the NGS data with the data from MLPA revealed that the sensitivity was 100%, whereas the specificity was 95%. Taken together, this study validates a one-step bioinformatics work-flow to call germline BRCA1/2 CNVs using data obtained by NGS of a breast cancer gene panel. The work-flow represents a robust and easy-to-use method for full BRCA1/2 screening, which can be easily implemented in routine diagnostic testing and adapted to genes other than BRCA1/2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, accompanied by concomitant and adjuvant temozolomide ...chemotherapy and radiotherapy. Malignant cells escape surgical resection by migrating into the brain parenchyma, where they give rise to the recurrent tumor. Based on gene expression, the tumor core can be subtyped into mesenchymal, proneural and classical areas, each being associated with differences in genetic alterations and cellular composition. In contrast, the tumor periphery where migrating tumor cells infiltrate brain parenchyma is less characterized in patients. Using spatial transcriptomics (n = 11), we show that specific malignant states colocalize in tumor core areas with necrosis and microvascular proliferation. Malignant cells within proneural or mesenchymal subtyped cores displayed, as expected, many differences in genetic expression, although such differences disappeared in the tumor periphery. Malignant cells residing in the tumor periphery had increased expression of genes related to neurodevelopmental pathways and synaptic connectivity. Our findings show similarities in cellular states across tumor subtypes with implications for post-operative treatment and provide an updated view of the spatial landscape of glioblastomas.
Citation Format: Dylan Harwood, Vilde Pedersen, Nicolai S. Bager, Ane Y. Schmidt, Tobias O. Stannius, Ausrine Areskeviciute, Knud Josefsen, Dorte S. Nørøxe, David Scheie, Hannah E. Rostalski, Ulrik Lassen, Frederik O. Bagger, Joachim Weischenfeldt, Dieter H. Heiland, Kristoffer Vitting-Seerup, Signe R. Michaelsen, Bjarne W. Kristensen. Glioblastoma cells increase expression of neurodevelopmental programs and synaptic connectivity in the tumor periphery abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1144.
While consensus regarding the return of secondary genomic findings in the clinical setting has been reached, debate about such findings in the research setting remains. We developed a hybrid, ...research-clinical translational genomics process for research exome data coupled with a CLIA-validated secondary findings analysis. Eleven intramural investigators from ten institutes at the National Institutes of Health piloted this process. Nearly 1,200 individuals were sequenced and 14 secondary findings were identified in 18 participants. Positive secondary findings were returned by a genetic counselor following a standardized protocol, including referrals for specialty follow-up care for the secondary finding local to the participants. Interviews were undertaken with 13 participants 4 months after receipt of a positive report. These participants reported minimal psychologic distress within a process to assimilate their results. Of the 13, 9 reported accessing the recommended health care services. A sample of 107 participants who received a negative findings report were surveyed 4 months after receiving it. They demonstrated good understanding of the negative secondary findings result and most expressed reassurance (64%) from that report. However, a notable minority (up to 17%) expressed confusion regarding the distinction of primary from secondary findings. This pilot shows it is feasible to couple CLIA-compliant secondary findings to research sequencing with minimal harms. Participants managed the surprise of a secondary finding with most following recommended follow up, yet some with negative findings conflated secondary and primary findings. Additional work is needed to understand barriers to follow-up care and help participants distinguish secondary from primary findings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Investigation of signaling pathways altered by recurrent gene mutations and their clinical impact in a consecutive cohort of patients with newly diagnosed chronic lymphocytic leukemia (CLL). The ...heterogeneous clinical course and genetic complexity of CLL warrant improved molecular prognostication. However, the prognostic value of recurrent mutations at the time of diagnosis remains unclear.
We sequenced samples from 314 consecutive, newly diagnosed patients with CLL to investigate the clinical impact of 56 recurrently mutated genes assessed by next-generation sequencing.
Mutations were identified in 70% of patients with enrichment among IGHV unmutated cases. With 6.5 years of follow-up, 15 mutated genes investigated at the time of diagnosis demonstrated significant impact on time to first treatment (TTFT). Carrying driver mutations was associated with shorter TTFT and poor overall survival. For outcome from CLL diagnosis, the number of signaling pathways altered by driver mutations stratified patients better than the number of driver mutations. Moreover, we demonstrated gradual impact on TTFT with increasing number of altered pathways independent of CLL-IPI risk. Thus, a 25-gene, pathway-based biomarker assessing recurrent mutations refines prognostication in CLL, in particular for CLL-IPI low- and intermediate-risk patients. External validation emphasized that a broad gene panel including low burden mutations was key for the biomarker based on altered pathways.
We propose to include the number of pathways altered by driver mutations as a biomarker together with CLL-IPI in prospective studies of CLL from time of diagnosis for incorporation into clinical care and personalized follow-up and treatment.
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