Mutant KRAS and TP53 with high mutation allelic frequency in ctDNA as poor outcome predictors in metastatic pancreatic cancer.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15763-e15763
Author(s):  
Shasha Guan ◽  
Yan Shi ◽  
Quanli Han ◽  
Jie Li ◽  
Yao Lv ◽  
...  

e15763 Background: This study was to investigate the feasibility and the prognostic value of circulating tumor DNA (ctDNA) in metastatic pancreatic cancer (MPC). Methods: From 2015 to 2018 in our center, 40 MPC patients treated with nab-paclitaxel based first-line chemotherapy were prospectively collected both tumor tissue and blood samples, in which the genomic profiling of 425 genes was identified by next-generation sequencing. High mutation allelic frequency (MAF) was defined > 30% and > 5% in tumor tissue and blood, respectively. Kappa statistics were used to compare mutant (mt) genes in tissue and ctDNA. Progression-free and overall survival (PFS, OS) were assessed with Kaplan-Meier and Cox methods. Results: Among 40 MPC patients, tumor tissue and blood samples were available in 34 and 38 patients for somatic and germline alternation test, respectively. The most commonly mutant gene were KRAS (31/34 in tissue with a median MAF of 29.4%, 29/38 in ctDNA with a mMAF of 8.2%), and TP53 (28/34 in tissue with a mMAF of 31.1%, 25/38 in ctDNA with a mMAF of 7.4%). Moderate agreement was seen between ctDNA and tumor tissue (mt KRAS: κ = 0.54, P = 0.001; mt TP53: κ = 0.74, P < 0.001). Mutation in CDNK2A and SMAD4 genes were detected in 8 and 6 patients in tissue and ctDNA, respectively. Germline alternation was found in 7 genes in 9 patients (9/40). High MAF of mt KRAS (r = 0.51, P = 0.005) or mt TP53 (r = 0.50, P = 0.005) in ctDNA was correlated with high CA199 levels (> 5000 u/ml) at baseline. MT KRAS in tissue with high MAF was associated with poor OS (high 7.5m vs low 10.1m, P = 0.001) in univariate and multivariate analyses (HR 3.87, 95%CI 1.47 to 10.19). Univariate analyses showed mt KRAS and mt TP53 in ctDNA with high MAF were associated with poor PFS ( KRAS and TP53: high 3.4m and 3.0m vs low 6.1m and 5.7m, P = 0.001 and P = 0.004, respectively) and OS ( KRAS and TP53: high 5.3m and 5.3m vs low 12.6m and 10.1m, P < 0.001, respectively). The presence of ctDNA in any above four mt driver gene with high MAF was associated with poor PFS (HR 3.79, 95%CI 1.71 to 8.42) and OS (HR 7.21, 95%CI 2.69 to 19.34) in multivariate COX model, when adjusted by age, sex, tumor differentiation, and baseline CA199 level. Conclusions: The presence of mt KRAS and mt TP53 with high MAF in ctDNA was associated with worse PFS and OS in MPC patients. Peripheral ctDNA testing demonstrated an alternative promising prognostic biomarker for MPC patients before treatment.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3009-3009
Author(s):  
Emmanuel S. Antonarakis ◽  
Zheng Kuang ◽  
Hanna Tukachinsky ◽  
Christine Parachoniak ◽  
Andrew David Kelly ◽  
...  

3009 Background: The increased use of ctDNA CGP has paralleled increased detection and interest in CH, which can confound CGP results from ctDNA or tissue, and can be associated with hematologic and cardiovascular morbidity. However, paired-depth sequencing of white blood cells (WBC) for confirmation of CH is not widely available. We here study the prevalence of inferred CH (iCH), which refers to incidental detection on routine clinical CGP of variants attributable to CH due to their known CH association and their negligible prevalence in solid tumors. Methods: A database of clinical CGP results was reviewed, including two 324-gene NGS panels for tumor tissue (FoundationOne CDx) and plasma ctDNA (FoundationOne Liquid CDx). Analysis was limited to NSCLC, breast, prostate, colorectal, and pancreatic cancers. iCH was defined as any pathogenic mutation in ASXL1, DNMT3A, and TET2, and prespecified mutations in JAK2, SF3B1, U2AF1, MYD88, IDH2, MPL, CBL. Variant allelic frequency (VAF) > 2% was considered clinically significant and VAF > 10% was considered high risk. Results: 100,905 total cases were studied; median age was 65 for tissue CGP and 68 for ctDNA. iCH was more commonly detected in ctDNA (1468/2891, 51%) than in tissue (9416/97993, 10%). Among cases with any iCH detected, multiple iCH mutations were seen more commonly in ctDNA (640/2891, 22%) than in tissue (987/98014, 1%). Focusing on clinically significant iCH ( > 2% VAF), prevalence remained higher in ctDNA (22%, 637) than in tissue (8%, 7878), while the higher sensitivity of ctDNA testing identified more low level iCH (< 2% VAF, 40% in ctDNA, 2% in tissue). Across cancer types, iCH > 2% was consistently more common in ctDNA (Table). As expected, prevalence of iCH > 2% increased with age (continuous variable, p < 0.001). High risk iCH ( > 10% VAF) was seen in 4% of total cases (most commonly ASXL1, TET2, DNMT3A); 1% of all cases had multiple clinically significant iCH variants ( > 2% VAF). Focusing on a subset of 439 cases with both tissue and ctDNA results (median 1.5 months between samples), 290 iCH mutations were detected in ctDNA (median VAF 1%) but only 38 in tissue (median VAF 9%). Conclusions: Inferred CH is common on somatic CGP of cancer patients, with a high prevalence in ctDNA likely due to the deeper sequencing depth and WBC contamination. For the minority of patients with high VAF iCH, further research is needed to understand whether this might be representative of an occult hematologic condition deserving of further evaluation.[Table: see text]


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15769-e15769
Author(s):  
Yan Shi ◽  
Shasha Guan ◽  
Quanli Han ◽  
Jie Li ◽  
Yao Lv ◽  
...  

e15769 Background: Emerging evidence showed circulating tumor DNA (ctDNA) may be used as biomarker for monitoring tumor response to chemotherapy in pancreatic cancer. This pilot study was to evaluate the clinical application of dynamic assessment ctDNA in MPC. Methods: From December 2016 to June 2018 in our center, 29 MPC patients treated with nab-paclitaxel based first-line chemotherapy (NS or N plus Gemcitabine, NG) had at least 2 ctDNA tests were included for analysis. Plasma samples were prospectively collected at baseline and periodical follow-ups until progression, death, or withdrawal of consent. Next-generation sequencing for a panel of 425 genes covering a wide range of cancer-related loci was performed to profile ctDNA. Progression of ctDNA was defined as increased mutation allelic frequency (MAF) of common mutant gene from baseline or nadir, or the presence of new gene alternations. The clinical relevance of the common alteration, and its dynamic changes in ctDNA were analyzed, and compared to conventional imaging response and survival. Results: In our patient cohort, the best overall response of partial response (PR) was 48.3% (14/29). By February 2019, 18 patients passed away with median follow-up of 9.7 months. At baseline, 22 patients (75.9%, N = 29) had at least one common driver gene alterations ( KRAS, TP53, CDKN2A, SMAD4) detected in ctDNA. Mutant KRAS and TP53 were identified in 72.4% and 62.1% patients with a median MAF of 5.8% and 4.7%, respectively. Of 14 patients achieved PR on image, MAF of the mutant driver genes found declined significantly or mutant gene disappeared. At the time of clinical progressive disease (PD), 24 patients had evaluable image and ctDNA results whereas both demonstrated PD in 23 (95.8%), including 9 found earlier progression of ctDNA with median time of 1.93 months compared to image findings. Among 22 patients with any of the above 4 mutant driver genes in ctDNA at baseline, 13 patients demonstrated significant reduction of MAF (reduction to < 1% or undetectable) within 6 weeks, who had a longer progression free survival (PFS, reduction 6.6m vs no reduction 3.4m, P = 0.001) and overall survival (OS, reduction 12.6m vs no reduction 5.4m, P = 0.001), compared to those who had an increased or stable MAF. Conclusions: Our initial findings demonstrated the changes in MAF of 4 common driver genes in ctDNA was well correlated with treatment response to chemotherapy, PFS and OS in MPC. Peripheral ctDNA was a potential reliable alternative biomarker for efficacy and progression prediction in MPC.


2017 ◽  
Vol 1 (S1) ◽  
pp. 62-62
Author(s):  
Jose Ignacio Varillas ◽  
Jinling Zhang ◽  
Weian Sheng ◽  
Kangfu Chen ◽  
Isis Barnes ◽  
...  

OBJECTIVES/SPECIFIC AIMS: The goal of this research is to use circulating tumor cells (CTC) enumeration and characterization to monitor anticancer treatment response. Emerging evidence strongly suggests the implications that epithelial-to-mesenchymal transition may have in cancer metastasis. Consequently, we hope to elucidate the significance of mesenchymal and stem-like CTCs in the peripheral blood of metastatic pancreatic cancer patients by analyzing the prevalence and frequency trends of CD133+ CTCs, as they relate to clinical events. We also hope to determine if there is a correlation between EpCAM+ CTCs and CD133+ CTCs numbers with tumor size, disease stage, and patient clinical outcome. METHODS/STUDY POPULATION: Blood samples of patients with metastatic pancreatic cancer (stage IV) were obtained from the University of Florida Health Cancer Center after informed consent through an IRB-approved protocol. CTC capture, characterization, and enumeration was performed on the blood of these cancer patients during their anticancer treatment. Patients had blood drawn for this purpose at time points aligned with clinical phlebotomy (every 2 weeks). CTC capture was performed by introducing treated patient blood samples into antibody-functionalized microdevices. The PDMS devices were functionalized by immobilizing either anti-EpCAM or anti-CD133, through an avidin-biotin complex. After capture, cells were fixated and permeabilized with 4% paraformaldehyde and 0.2% Triton X-100, respectively. Three-color immunocytochemistry (anti-cytokeratin-FITC, anti-CD45-PE, and DAPI) was performed to identify CTCs from nonspecifically captured blood cells. To be counted as a CTC, based on the FDA-approved technical definition, a cell with the appropriate cell size and morphology must be nucleated (DAPI+), express cytokeratin (CK+), and lack the leukocytic CD45 marker (CD45−). RESULTS/ANTICIPATED RESULTS: We tested the clinical utility of the device for monitoring the response of patients with advanced pancreatic cancer to a chemotherapy treatment consisting of anticancer drugs including 5-fluorouracil, leucovorin, oxaliplatin, and dasatinib. We have detected EpCAM+ CTCs in 47/47 (100%) and CD133+ CTCs in 41/47 (87.2%) of blood samples, coming from a cohort of 16 patients. We studied the correlation between the CTC numbers and the clinical result of patients in the study. We found that the size and changes in the size of the primary tumor (confirmed by CT scans) correlated with the frequency and increase/decrease trends in the number of CTCs detected. We expect to find some relationship between the number of detected CD133+ CTCs, or rather stem-like CTCs, and the clinical outcome of patients (eg, disease progression leading to withdrawal from study). DISCUSSION/SIGNIFICANCE OF IMPACT: Enumeration of patient CTCs and stem-like CTCs at different stages of a patient’s treatment may correlate with disease stage and prognosis, and prove useful in monitoring early recurrence, patient-specific treatment response, and newly acquired resistances; all of which would aid in providing guidance for the next step in clinical intervention. This type of liquid biopsy technology has great potential to make an impact in the future of personalized medicine and point-of-care diagnostics, as well as become a sturdy tool for translational research.


2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 457-457 ◽  
Author(s):  
Gillian Vandekerkhove ◽  
Jean-Michel Lavoie ◽  
Matti Annala ◽  
Nora Sundahl ◽  
Takeshi Sano ◽  
...  

457 Background: Biomarkers are urgently needed to facilitate tumor molecular stratification in metastatic urothelial carcinoma (mUC), thus potentially enabling patient selection for targeted- and immuno-therapies. We aimed to assess concordance for clinically-relevant driver gene alterations between same-patient tumor tissue and ctDNA. Methods: Whole blood samples were collected from 90 mUC patients (162 samples in total) for next-generation sequencing of cell-free DNA (cfDNA) and leukocyte DNA. Deep targeted sequencing was performed across a custom 50 bladder cancer gene panel (median cfDNA depth of 986x). Matched archival primary tissue and/or metastatic tissue biopsy was available from 65 patients, and profiled using the same assay. Results: 81% of mUC patients (73/90) had ctDNA fractions above 2% in at least one blood collection (median ctDNA fraction 22%). A high tumor mutation burden (≥25 mutations per Mb) was observed in ctDNA from 20 patients (27%). From ctDNA, TP53 and ARID1A were mutated in 64% and 29% of patients, respectively. Tissue from distant metastatic lesions was available from 17 patients; 82% (62/76) of coding somatic mutations identified were independently detected in the matched ctDNA sample; however, 7/14 discordant calls were attributable to the paired sample having a low ctDNA fraction. Similarly, 89% (88/99) of coding somatic mutations detected in archival primary tissue (cystectomy or nephrectomy) were present in later cfDNA collections. Sequencing multiple sites from archival cystectomies revealed spatially and genomically distinct subclones in 2/4 cases. Conclusions: In mUC, tumor tissue and ctDNA demonstrate remarkably high concordance; our findings support the use of either approach in the characterization of truncal driver gene alterations.


2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 655-655 ◽  
Author(s):  
Arthur Winer ◽  
Elizabeth A. Handorf ◽  
Efrat Dotan

655 Background: The dosing of Gemcitabine and Nab-Paclitaxel (GA), a frontline regimen to treat metastatic pancreatic cancer (mPC), is frequently altered from the traditional dosing schedule (TDS) of day 1, 8, and 15 of a 28 day cycle to a modified dosing schedule (MDS) of 2 doses/cycle. Previous work showed that overall survival (OS) was similar between patients (pts) treated with the MDS vs the TDS. We sought to analyze a larger real-world database to assess these trends. Methods: We retrospectively analyzed de-identified pts with mPC ≥ 65 y/o treated with GA in the Flatiron Health nationwide EHR-derived database. Demographics, treatments (tx), and outcomes were collected. Pts were grouped as either starting with the TDS or MDS. Analysis included time on treatment (TOT) as well as OS. A Cox model was used to test non-inferiority of the MDS vs the TDS for both TOT and OS, adjusting performance status, age, race, gender, and line of therapy (LOT). The upper bound for non-inferiority was a Hazard Ratio (HR) = 1.2. Results: 1497 pts were treated between 1/1/14-5/31/19; 883 pts with the TDS and 614 with the MDS. Median TDS age was 72 (65-85) and MDS was 73 (65-84) (p<0.001). 1237 pts received first- line GA; 60% received the TDS, 40% the MDS. The use of the TDS vs MDS did not vary significantly by LOT, gender, or race, but more pts with a PS of ≥2 received the MDS (p=0.03). In the first-line, outcomes were better for the TDS vs the MDS (unadjusted median TOT 5.3 vs 3.2 mo, p<0.001, OS 9.2 vs 5.3 mo; p<0.001), with consistent results in the ≥ second-line. The MDS did not meet its non-inferiority boundary: first-line TOT HR=1.4 [95% CI 1.2-1.6]; second+ line TOT HR=1.3 [95% CI 1.0-1.7]; first-line OS HR=1.6 [95% CI 1.4-1.8]; second+ line OS HR=1.3 [95% CI 1.0-1.8]. Results were consistent when additionally stratified by PS 0-1 vs 2+. Conclusions: In this large real-world cohort, first-line GA tx with a MDS did not meet criteria for non-inferiority for TOT and OS vs a TDS in older adults with mPC. With the caveats of potential confounding that exist in a de-identified retrospective database, these results suggest that dose intensity may be important in pts with mPC. Further prospective studies are necessary to ensure we utilize effective tx strategies in older adults with mPC.


Oncotarget ◽  
2017 ◽  
Vol 9 (2) ◽  
pp. 2076-2085 ◽  
Author(s):  
Andreas W. Berger ◽  
Daniel Schwerdel ◽  
Thomas J. Ettrich ◽  
Alexander Hann ◽  
Stefan A. Schmidt ◽  
...  

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