scholarly journals Characterization and Clinical Utility of BRAFV600 Mutation Detection Using Cell-Free DNA in Patients with Advanced Melanoma

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3591
Author(s):  
Piotr Rutkowski ◽  
Patrick Pauwels ◽  
Joseph Kerger ◽  
Bart Jacobs ◽  
Geert Maertens ◽  
...  
Keyword(s):  
Objective Response ◽  
Treatment Phase ◽  
Progression Free Survival ◽  
Cell Free Dna ◽  
Mutation Status ◽  
Free Survival ◽  
Free Dna ◽  
Phase 2 Study ◽  
Melanoma Patients ◽  
Test Result

Tissue-based tests for BRAFV600 mutation-positive melanoma involve invasive biopsy procedures, and can lead to an erroneous diagnosis when the tumor samples degrade. Herein, we explored a minimally invasive, cell-free deoxyribonucleic acid (cfDNA)-based platform, to retest patients for BRAFV600 mutations. This phase 2 study enrolled adult patients with unresectable/metastatic melanoma. A prescreening testing phase evaluated the concordance between a prior tissue-based BRAFV600 mutation test result and a subsequent plasma cfDNA-based test result. A treatment phase evaluated the patients who were confirmed as BRAFV600 mutation-positive, and were treated with cobimetinib plus vemurafenib. It was found that 35/54 patients (64.8%) with a mutant BRAF status by prior tissue test had a positive BRAFV600 mutation with the cfDNA test. Further, 7/118 patients (5.9%) with a wild-type BRAF status had a positive BRAFV600 mutation cfDNA test; tissue retests on archival samples confirmed BRAFV600 mutation positivity in 5/7 patients (71.4%). One of these patients received BRAF pathway-targeted therapy (cobimetinib plus vemurafenib), and had progression-free survival commensurate with previous experience. In the overall cobimetinib plus vemurafenib-treated population, 29/36 patients (80.6%) had an objective response. The median progression-free survival was 13.6 months (95% confidence interval, 9.5–16.5). Cell-free DNA–based tests may be a fast and convenient option to identify BRAF mutation status in melanoma patients, and help inform treatment decisions.

scholarly journals Prognostic Implications of Multiplex Detection of KRAS Mutations in Cell-Free DNA from Patients with Pancreatic Ductal Adenocarcinoma

2018 ◽  
Vol 64 (4) ◽  
pp. 726-734 ◽  
Author(s):  
Min Kyeong Kim ◽  
Sang Myung Woo ◽  
Boram Park ◽  
Kyong-Ah Yoon ◽  
Yun-Hee Kim ◽  
...  
Keyword(s):  
Kras Mutation ◽  
Progression Free Survival ◽  
Ductal Adenocarcinoma ◽  
Multiplex Detection ◽  
Kras Mutations ◽  
Cell Free Dna ◽  
Free Survival ◽  
Free Dna ◽  
Fractional Abundance ◽  
Prognostic Implications

Abstract BACKGROUND Cell-free DNA (cfDNA) is known to provide potential biomarkers for predicting clinical outcome, but its value in pancreatic ductal adenocarcinoma (PDAC) has not been fully evaluated. The aim of this study was to evaluate the clinical applicability of quantitative analysis of multiplex KRAS mutations in cell-free DNA from patients with PDAC. METHODS A total of 106 patients with PDAC were enrolled in this prospective study. The concentration and fraction of KRAS mutations were determined through multiplex detection of KRAS mutations in plasma samples by use of a droplet digital PCR kit (Bio-Rad). RESULTS KRAS mutations were detected in 96.1% of tissue samples. Eighty patients (80.5%) harbored KRAS mutations in cfDNA, with a median KRAS mutation concentration of 0.165 copies/μL and a median fractional abundance of 0.415%. Multivariable analyses demonstrated that the KRAS mutation concentration [hazard ratio (HR), 2.08; 95% CI, 1.20–3.63] and KRAS fraction (HR, 1.73; 95% CI, 1.02–2.95) were significant factors for progression-free survival. KRAS mutation concentration (HR, 1.97; 95% CI, 1.05–3.67) also had prognostic implications for overall survival. Subgroup analyses showed that KRAS mutation concentration and fractional abundance significantly affected progression-free survival in resectable PDAC (P = 0.016). Moreover, when combined with the cancer biomarker CA19-9, the KRAS mutation concentration in cfDNA showed additive benefits for the prediction of overall survival. CONCLUSIONS This study demonstrates that multiplex detection of KRAS mutations in plasma cfDNA is clinically relevant, providing a potential candidate biomarker for prognosis of PDAC.

Circulating tumor DNA (ctDNA) dynamics associate with treatment response and radiological progression-free survival (rPFS): Analyses from a randomized phase II trial in metastatic castration-resistant prostate cancer (mCRPC).

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 5508-5508
Author(s):  
Jane Goodall ◽  
Zoe June Assaf ◽  
Zhen Shi ◽  
George Seed ◽  
Liangxuan Zhang ◽  
...  
Keyword(s):  
Treatment Response ◽  
Phase Ii ◽  
Cox Model ◽  
Progression Free Survival ◽  
Castration Resistant Prostate Cancer ◽  
Radiological Progression ◽  
Cell Free Dna ◽  
Free Survival ◽  
Free Dna ◽  
Randomized Phase Ii

5508 Background: ctDNA can inform on prognosis, treatment response and survival. We evaluated ctDNA in serial plasma samples from patients enrolled in A.MARTIN (NCT01485861), a randomized phase II study of abiraterone with or without ipatasertib in patients with mCRPC. Methods: Blood was collected in cell-free DNA Streck tubes from 216 patients at 3 time points; baseline, C3D1 and end of treatment. Cell-free DNA (cfDNA) was extracted from plasma using a Circulating DNA Kit (Qiagen) on a QIASymphony machine (Qiagen). 25ng of extracted cfDNA was used in library preparation, constructed with a custom designed, 58 gene, QIAseq Targeted DNA panel (Qiagen) enriched for PI3K/AR pathway genes. Samples were sequenced to mean depth of 3394x on a NextSeq500 machine. Unless otherwise noted, all analyses combine patients across the 3 study arms, and reported p-values are unadjusted. Results: Baseline (BL) ctDNA positivity correlated with radiological progression-free survival (rPFS; HR: 1.8 [95% CI 1.3-2.6], p < 0.01); this association with rPFS was maintained in a multivariate cox model with > 5 baseline clinical variables (HR: 1.6 [95% CI 1.1-2.4]; p = 0.011). Patients with a C3D1 reduction in ctDNA had superior rPFS compared to patients with a C3D1 increase in ctDNA (HR: 2 [95% CI 1.3-3.2], p < 0.01). The rate of ctDNA clearance at C3D1 was higher in the Ipatasertib 400mg arm compared to placebo (56.3% versus 24.4%, p < 0.01). We find that changes in ctDNA associated with best confirmed overall response (p = 0.024); CR patients had the greatest reduction in ctDNA (mean of -23.4%), followed by PR (-16.3%), then SD (-4.1%), and lastly PD patients (-1.3%). Changes in ctDNA levels correlated with SLD changes (rs = 0.289, p = 0.05), and also PSA changes (rs = 0.33, p < 0.01). Changes in ctDNA were associated with rPFS in a multivariate cox analysis that included PSA change (p < 0.01), as well as in a separate multivariate analysis that included SLD change (p < 0.01). Lastly, we explored CNVs and observed emerging resistance mutations in progression samples, including alterations in TP53, AR, FOXA, PTEN, and PI3K/AKT pathway genes. Conclusions: ctDNA analyses may help (i) identify poorer prognosis disease at baseline, (ii) inform on treatment response (CR/PR/SD/PD) and radiological progression free survival (rPFS) in on-treatment (C3D1) samples, and (iii) can elucidate emerging resistance mechanisms at disease progression. Clinical trial information: NCT01485861 .

scholarly journals The PEMDAC phase 2 study of pembrolizumab and entinostat in patients with metastatic uveal melanoma

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lars Ny ◽  
Henrik Jespersen ◽  
Joakim Karlsson ◽  
Samuel Alsén ◽  
Stefan Filges ◽  
...  
Keyword(s):  
Uveal Melanoma ◽  
Median Overall Survival ◽  
Objective Response ◽  
Progression Free Survival ◽  
Epigenetic Therapy ◽  
Phase 2 ◽  
Free Survival ◽  
Phase 2 Study ◽  
Phase 2 Clinical Trial ◽  
Registration Number

AbstractPreclinical studies have suggested that epigenetic therapy could enhance immunogenicity of cancer cells. We report the results of the PEMDAC phase 2 clinical trial (n = 29; NCT02697630) where the HDAC inhibitor entinostat was combined with the PD-1 inhibitor pembrolizumab in patients with metastatic uveal melanoma (UM). The primary endpoint was objective response rate (ORR), and was met with an ORR of 14%. The clinical benefit rate at 18 weeks was 28%, median progression free survival was 2.1 months and the median overall survival was 13.4 months. Toxicities were manageable, and there were no treatment-related deaths. Objective responses and/or prolonged survival were seen in patients with BAP1 wildtype tumors, and in one patient with an iris melanoma that exhibited a UV signature. Longer survival also correlated with low baseline ctDNA levels or LDH. In conclusion, HDAC inhibition and anti-PD1 immunotherapy results in durable responses in a subset of patients with metastatic UM.Trial registration ClinicalTrials.gov registration number: NCT02697630 (registered 3 March 2016). EudraCT registration number: 2016–002114-50.

scholarly journals Association of plasma cell-free DNA with survival in patients with IDH wild-type glioblastoma

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Stephen J Bagley ◽  
Jacob Till ◽  
Aseel Abdalla ◽  
Hareena K Sangha ◽  
Stephanie S Yee ◽  
...  
Keyword(s):  
Plasma Cell ◽  
Dna Methyltransferase ◽  
Methylation Status ◽  
Progression Free Survival ◽  
Wild Type ◽  
Cell Free Dna ◽  
Free Survival ◽  
Methylguanine Dna Methyltransferase ◽  
Free Dna ◽  
Post Hoc

Abstract Background We aimed to determine whether plasma cell-free DNA (cfDNA) concentration is associated with survival in patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM). Methods Pre-operative and post-chemoradiotherapy blood samples were prospectively collected from patients with newly diagnosed IDH wild-type GBM. Patients underwent surgical resection or biopsy and received adjuvant radiotherapy with concomitant temozolomide. Cell-free DNA (cfDNA) was isolated from plasma and quantified using SYBR Green-based q polymerase chain reaction (qPCR). Results Sixty-two patients were enrolled and categorized into high vs. low cfDNA groups relative to the pre-operative median value (25.2 ng/mL, range 5.7–153.0 ng/mL). High pre-operative cfDNA concentration was associated with inferior PFS (median progression-free survival (PFS), 3.4 vs. 7.7 months; log-rank P = .004; hazard ratio [HR], 2.19; 95% CI, 1.26–3.81) and overall survival (OS) (median OS, 8.0 vs. 13.9 months; log-rank P = .01; HR, 2.43; 95% CI, 1.19–4.95). After adjusting for risk factors, including O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status, pre-operative cfDNA remained independently associated with PFS (HR, 2.70; 95% CI, 1.50–4.83; P = .001) and OS (HR, 2.65; 95% CI, 1.25–5.59; P = .01). Post-hoc analysis of change in cfDNA post-chemoradiotherapy compared to pre-surgery (n = 24) showed increasing cfDNA concentration was associated with worse PFS (median, 2.7 vs. 6.0 months; log-rank P = .003; HR, 4.92; 95% CI, 1.53–15.84) and OS (median, 3.9 vs. 19.4 months; log-rank P &lt; .001; HR, 7.77; 95% CI, 2.17–27.76). Conclusions cfDNA concentration is a promising prognostic biomarker for patients with IDH wild-type GBM. Plasma cfDNA can be obtained noninvasively and may enable more accurate estimates of survival and effective clinical trial stratification.

scholarly journals Subcutaneous envafolimab monotherapy in patients with advanced defective mismatch repair/microsatellite instability high solid tumors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jian Li ◽  
Yanhong Deng ◽  
Weijie Zhang ◽  
Ai-Ping Zhou ◽  
Weijian Guo ◽  
...  
Keyword(s):  
Solid Tumors ◽  
Response Rate ◽  
Objective Response ◽  
Progression Free Survival ◽  
Single Domain ◽  
Free Survival ◽  
Phase 2 Study ◽  
Duration Of Response ◽  
Previously Treated ◽  
Grade 3

Abstract Background Monoclonal antibodies targeting programmed death ligand 1 (PD-L1) signaling currently approved for defective mismatch repair (dMMR)/microsatellite instability high (MSI-H) tumors must be delivered by intravenous infusion. Envafolimab, a humanized single-domain anti-PD-L1 antibody fused to an Fc fragment, represents a potential advance because it can be conveniently administered subcutaneously. Methods This open-label, single-arm, phase 2 study evaluated the efficacy and safety of envafolimab in patients with previously treated advanced dMMR/MSI-H tumors from 25 clinical sites across China. Adults with histologically confirmed locally advanced or metastatic malignant dMMR/MSI-H solid tumors received weekly 150 mg subcutaneous envafolimab injections in a 28-day treatment cycle. The primary efficacy endpoint was the objective response rate (assessed by a blinded independent review committee). Secondary efficacy outcomes were disease control rate, duration of response, progression-free survival, and overall survival. Results One hundred and three patients (65 with colorectal cancer, 18 with gastric cancer, and 20 with other solid tumors) were enrolled. Median follow-up was 11.5 months. The objective response rate was 42.7% (95% confidence interval [CI] 33.0–52.8), and the disease control rate was 66.0% (95% CI 56.0–75.1). Median duration of response was not reached; the duration of response rate at 12 months was 92.2% (95% CI 77.5–97.4). Median progression-free survival was 11.1 months (95% CI 5.5 to not evaluable). Overall survival at 12 months was 74.6% (95% CI 64.7–82.1). Sixteen patients (16%) had at least one grade 3 or 4 related treatment-emergent adverse event. No grade 5 treatment-emergent adverse events related to envafolimab were reported. Injection site reactions, all grade 1–2, were reported in nine patients (9%), but there were no infusion reactions. Eight patients (8%) had grade 3 or 4 immune-related adverse events. Conclusions This is the first pivotal phase 2 study to examine the efficacy and safety of a single-domain immune checkpoint antibody in the treatment of cancer. Envafolimab was effective and had acceptable safety in the treatment of previously treated advanced dMMR/MSI-H solid tumors. As the first single-domain PD-L1-targeting antibody administered by rapid subcutaneous injection, envafolimab has the potential to be a significant advance in the treatment of cancer. Trial registration ClinicalTrials.gov, NCT03667170. Registered 10 September 2018—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03667170.

scholarly journals Prognostic Role of RASSF1A, SOX17 and Wif-1 Promoter Methylation Status in Cell-Free DNA of Advanced Gastric Cancer Patients

2021 ◽  
Vol 20 ◽  
pp. 153303382097327
Author(s):  
Evangelos I. Karamitrousis ◽  
Ioanna Balgkouranidou ◽  
Nikolaos Xenidis ◽  
Kyriakos Amarantidis ◽  
Eirini Biziota ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Overall Survival ◽  
Advanced Gastric Cancer ◽  
Cancer Patients ◽  
Methylation Status ◽  
Progression Free Survival ◽  
Cell Free Dna ◽  
Free Survival ◽  
Free Dna ◽  
Gastric Cancer Patients

Epigenetic modification of several genes is a key component in the development of gastric cancer. The methylation status of RASSF1A, SOX17 and Wif-1 genes was evaluated in the cell free circulating DNA of 70 patients with advanced gastric cancer, using methylation-specific PCR. Patients with higher cell-free DNA concentration seem to have lower PFS, than patients with lower cell-free DNA concentration (p = 0.001). RASSF1A was the tumor suppressor gene, most frequently methylated in metastatic gastric cancer patients, followed by SOX17 and Wif-1 (74.3%, 60.0% and 47.1%, respectively). Patients having the SOX17 promoter methylated, had lower progression free survival and overall survival, than unmethylated ones (p < 0.001). Patients having the Wif-1 promoter methylated, had lower progression free survival and overall survival, than unmethylated ones (p = 0.001). Patients having the RASSF1A promoter methylated, had lower progression free survival and overall survival, than unmethylated ones (p = 0.004). Promoter methylation of the examined genes was significantly associated with a decrease in progression free survival and overall survival, comparing to that of patients without methylation. Simultaneous methylation of the above genes was associated with even worse progression free survival and overall survival. The methylation of RASSF1A, SOX-17 and Wif-1 and genes, is a frequent epigenetic event in patients with advanced gastric cancer.

scholarly journals RTID-05. INDIGO: A GLOBAL, RANDOMIZED, DOUBLE-BLIND, PHASE 3 STUDY OF VORASIDENIB (AG-881) VS PLACEBO IN PATIENTS WITH RESIDUAL/RECURRENT GRADE II GLIOMA WITH AN ISOCITRATE DEHYDROGENASE 1/2 (IDH1/2) MUTATION

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii194-ii194
Author(s):  
Ingo Mellinghoff ◽  
Martin van den Bent ◽  
Jennifer Clarke ◽  
Elizabeth Maher ◽  
Katherine Peters ◽  
...  
Keyword(s):  
High Risk ◽  
Dose Escalation ◽  
Objective Response ◽  
Data Monitoring Committee ◽  
Progression Free Survival ◽  
High Risk Population ◽  
Low Grade ◽  
Who Grade ◽  
Free Survival ◽  
Grade Ii

Abstract BACKGROUND Low-grade gliomas (LGGs; WHO grade II) are incurable and ultimately progress to high-grade gliomas. The current treatment options are surgery followed by observation (“watch and wait”) for patients with lower risk for disease progression or postoperative chemoradiotherapy (high-risk population). There are no approved targeted therapies. IDH1 and IDH2 mutations (mIDH1/2) occur in approximately 80% and 4% of LGGs, respectively, and promote tumorigenesis via neomorphic production of D-2-hydroxyglutarate. Vorasidenib, an oral, potent, reversible, brain-penetrant pan-inhibitor of mIDH1/2, was evaluated in 76 patients with glioma in two phase 1 studies (dose escalation and perioperative) and was associated with a favorable safety profile at daily doses below 100 mg. Preliminary clinical activity was observed in non-enhancing glioma patients in both studies, with an objective response rate (ORR) of 18.2% and median progression-free survival of 31.4 months in the dose escalation study. METHODS Approximately 366 patients will be randomized 1:1 to vorasidenib (50 mg QD) or matched placebo and stratified by 1p19q status (intact vs co-deleted). Key eligibility criteria: age ≥ 12 years; grade II oligodendroglioma or astrocytoma (per WHO 2016 criteria) not in need of immediate treatment and without high-risk features; centrally confirmed mIDH1/2 status; ≥ 1 surgery for glioma with most recent ≥ 1 year but ≤ 5 years before randomization, and no other anticancer therapy; Karnofsky performance status ≥ 80%; and centrally confirmed measurable, non-enhancing disease evaluable by magnetic resonance imaging. Crossover from placebo to the vorasidenib arm is permitted upon centrally confirmed radiographic progression per RANO-LGG criteria. Primary endpoint: progression-free survival assessed by independent review. Secondary endpoints: safety and tolerability, tumor growth rate assessed by volume, ORR, overall survival, and quality of life. Clinical data will be reviewed regularly by an independent data monitoring committee. The study is currently enrolling patients in the US, with additional countries planned (NCT04164901).

scholarly journals Effectiveness of nivolumab affected by prior cetuximab use and neck dissection in Japanese patients with recurrent or metastatic head and neck cancer: results from a retrospective observational study in a real-world setting

2021 ◽  
Author(s):  
Shin Kariya ◽  
Yasushi Shimizu ◽  
Nobuhiro Hanai ◽  
Ryuji Yasumatsu ◽  
Tomoya Yokota ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Dissection ◽  
Neck Cancer ◽  
Median Overall Survival ◽  
Response Rate ◽  
Objective Response ◽  
Progression Free Survival ◽  
Japanese Patients ◽  
Free Survival

Abstract Background To examine the effect of prior use of cetuximab and neck dissection on the effectiveness of nivolumab, we conducted a large-scale subgroup analysis in Japanese patients with recurrent/metastatic head and neck cancer. Methods Data on the effectiveness of nivolumab were extracted from patient medical records. All patients were analyzed for effectiveness by prior cetuximab use. In the analyses for prior neck dissection, only patients with locally advanced disease were included. Results Of 256 patients analyzed, 155 had received prior cetuximab. Nineteen of 50 patients with local recurrence underwent neck dissection. The objective response rate was 14.7 vs 17.2% (p = 0.6116), median progression-free survival was 2.0 vs 3.1 months (p = 0.0261), and median overall survival was 8.4 vs 12 months (p = 0.0548) with vs without prior cetuximab use, respectively. The objective response rate was 23.1 vs 25.9% (p = 0.8455), median progression-free survival was 1.8 vs 3.0 months (p = 0.6650), and median overall survival was 9.1 vs 9.9 months (p = 0.5289) with vs without neck dissection, respectively. Conclusions These findings support the use of nivolumab for patients with recurrent/metastatic head and neck cancer regardless of prior cetuximab use or neck dissection history. Trial registration number UMIN-CTR (UMIN000032600), Clinicaltrials.gov (NCT03569436)

scholarly journals Evaluation of efficacy and toxicity of nivolumab combined with or without docetaxel in patients with advanced NSCLC

2021 ◽  
Author(s):  
Yang Wang ◽  
Jun Nie ◽  
Ling Dai ◽  
Weiheng Hu ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Overall Survival ◽  
Advanced Nsclc ◽  
Objective Response ◽  
Progression Free Survival ◽  
Meaningful Improvement ◽  
Free Survival ◽  
Significant Difference ◽  
Grade 3 ◽  
Doublet Chemotherapy ◽  
Platinum Doublet

Abstract Background The combination of PD-1/PD-L1 inhibitor and chemotherapy has been clinically confirmed to be beneficial as the first-line treatment of patients with advanced NSCLC. This study aimed to assess the effect of nivolumab + docetaxel versus nivolumab monotherapy in patients with NSCLC after the failure of platinum doublet chemotherapy. Materials and methods The efficacy and toxicity of nivolumab + docetaxel combination therapy versus nivolumab monotherapy were compared in this retrospective study. Primary endpoint of the study was progression-free survival (PFS), and the secondary endpoints were objective response rate (ORR), overall survival (OS), and toxicity. Results Between November 2017 and December 2019, 77 patients were included in this study, with 58 patients in the nivolumab group and 19 in the nivolumab + docetaxel group. The median follow-up was 18 months, and the PFS was 8 months for patients receiving nivolumab + docetaxel and 2 months for those receiving nivolumab alone (p = 0.001), respectively. Nivolumab + docetaxel showed superior OS compared with nivolumab, with the median OS unreached versus 7 months (p = 0.011). Among patients without EGFR/ALK variation, compared to nivolumab monotherapy, nivolumab + docetaxel showed better PFS (p = 0.04) and OS (p  = 0.05). There was no significant difference in grade 3–4 adverse events (AEs) between the two groups (p = 0.253). Conclusions The combination of nivolumab and docetaxel demonstrated a meaningful improvement in progression-free survival and overall survival compared to nivolumab monotherapy, in patients with NSCLC after the failure of platinum doublet chemotherapy, irrespective of EGFR/ALK variation status.

scholarly journals P04.16 TP53 mutations in codon 273 is predictive of overall survival in astrocytoma patients

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii32-iii32
Author(s):  
H Noor ◽  
R Rapkins ◽  
K McDonald
Keyword(s):  
Overall Survival ◽  
Tp53 Mutation ◽  
Progression Free Survival ◽  
Low Grade Glioma ◽  
Low Grade ◽  
Wild Type ◽  
Mutation Status ◽  
Free Survival ◽  
Tp53 Mutations ◽  
Fresh Frozen

Abstract BACKGROUND Tumour Protein 53 (TP53) is a tumour suppressor gene that is mutated in at least 50% of human malignancies. The prevalence of TP53 mutation is much higher in astrocytomas with reports of up to 75% TP53 mutant cases. Rare cases of TP53 mutation also exist in oligodendroglial tumours (10–13%). P53 pathway is therefore an important factor in low-grade glioma tumorigenesis. Although the prognostic impact of TP53 mutations has been studied previously, no concrete concordance were reached between the studies. In this study, we investigated the prognostic effects of TP53 mutation in astrocytoma and oligodendroglioma. MATERIAL AND METHODS A cohort of 65 matched primary and recurrent fresh frozen tumours were sequenced to identify hotspot exons of TP53 mutation. Exons 1 to 10 were sequenced and pathogenic mutations were mostly predominant between Exons 4 and 8. The cohort was further expanded with 78 low grade glioma fresh frozen tissues and hotspot exons were sequenced. Selecting only the primary tumour from 65 matched tumours, a total of 50 Astrocytoma cases and 51 oligodendroglioma cases were analysed for prognostic effects of TP53. Only pathogenic TP53 mutations confirmed through COSMIC and NCBI databases were included in the over survival and progression-free survival analysis. RESULTS 62% (31/50) of astrocytomas and 16% (8/51) of oligodendrogliomas harboured pathogenic TP53 mutations. Pathogenic hotspot mutations in codon 273 (c.817 C>T and c.818 G>A) was prevalent in astrocytoma with 58% (18/31) of tumours with these mutations. TP53 mutation status was maintained between primary and recurrent tumours in 93% of cases. In astrocytoma, overall survival of TP53 mutant patients was longer compared to TP53 wild-type patients (p<0.01) but was not significant after adjusting for age, gender, grade and IDH1 mutation status. In contrast, astrocytoma patients with specific TP53 mutation in codon 273 showed significantly better survival compared to other TP53 mutant and TP53 wild-type patients combined (p<0.01) in our multivariate analysis. Time to first recurrence (progression-free survival) of TP53 mutant patients was significantly longer than TP53 wild-type patients (p<0.01) after adjustments were made, while TP53 mutation in codon 273 was not prognostic for progression-free survival. In oligodendroglioma patients, TP53 mutations did not significantly affect overall survival and progression-free survival. CONCLUSION In agreement with others, TP53 mutation is more prevalent in Astrocytoma and mutations in codon 273 are significantly associated with longer survival.

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