99P Pan-tumor characterization of KRAS mutations (KRASm) detected in circulating tumor DNA (ctDNA) and concordance with paired tissue

To determine mutations in the plasma KRAS gene in patients with colorectal cancer was the aim of this study. The material was obtained from 44 patients with colorectal cancer of different stages (T1-4N0-2bM0-1c). Plasma for the presence of KRAS gene mutation in circulating tumor DNA was investigated using digital droplet polymerase chain reaction (PCR). KRAS mutations in circulating tumor DNA isolated from 1 ml of plasma were detected in 13 (30%) patients with cancer of different stages. Of these, with stage II, there were 3 patients, with III - 5 and with IV - 5. Patients who did not have mutations in 1 ml of plasma were analyzed for mutations of KRAS in circulating tumor DNA isolated from 3 ml of plasma. Five more patients with KRAS mutations were found with II and III stages. The highest concentrations of circulating tumor DNA with KRAS mutation were found in patients with stage IV. The increase in plasma volume to 3 ml did not lead to the identification of mutations in I stage. This study showed that digital droplet PCR allows identification of circulating tumor DNA with the KRAS mutations in patients with stage II-IV of colon cancer. The results can be used to determine the degree of aggressiveness of the tumor at different stages of the disease, but not the 1st, and it is recommended to use a plasma volume of at least 3 ml.

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97 POSTER Analysis of EGFR and KRAS mutations in circulating tumor DNA (cTDNA) from plasma of NSCLC patients in phase 2 trials of XL647

European Journal of Cancer Supplements ◽

10.1016/s1359-6349(08)72029-9 ◽

2008 ◽

Vol 6 (12) ◽

pp. 33

Author(s):

F. Schimmoller ◽

N.A. Rizvi ◽

V.S. Vysotskaia ◽

R.P. Funke ◽

S. Dixon ◽

...

Keyword(s):

Circulating Tumor Dna ◽

Phase 2 ◽

Kras Mutations ◽

Nsclc Patients ◽

Tumor Dna

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Detection of KRAS Mutations in Circulating Tumor DNA by Digital PCR in Early Stages of Pancreatic Cancer

Clinical Chemistry ◽

10.1373/clinchem.2016.257469 ◽

2016 ◽

Vol 62 (11) ◽

pp. 1482-1491 ◽

Cited By ~ 55

Author(s):

Nora Brychta ◽

Thomas Krahn ◽

Oliver von Ahsen

Keyword(s):

Pancreatic Cancer ◽

Early Stage ◽

Digital Pcr ◽

Circulating Tumor Dna ◽

Surgical Removal ◽

Plasma Samples ◽

Kras Mutations ◽

Detection Rates ◽

Early Stages ◽

Tumor Dna

Abstract BACKGROUND Since surgical removal remains the only cure for pancreatic cancer, early detection is of utmost importance. Circulating biomarkers have potential as diagnostic tool for pancreatic cancer, which typically causes clinical symptoms only in advanced stage. Because of their high prevalence in pancreatic cancer, KRAS proto-oncogene, GTPase [KRAS (previous name: Kirsten rat sarcoma viral oncogene homolog)] mutations may be used to identify tumor-derived circulating plasma DNA. Here we tested the diagnostic sensitivity of chip based digital PCR for the detection of KRAS mutations in circulating tumor DNA (ctDNA) in early stage pancreatic cancer. METHODS We analyzed matched plasma (2 mL) and tumor samples from 50 patients with pancreatic cancer. Early stages (I and II) were predominant (41/50) in this cohort. DNA was extracted from tumor and plasma samples and tested for the common codon 12 mutations G12D, G12V, and G12C by chip-based digital PCR. RESULTS We identified KRAS mutations in 72% of the tumors. 44% of the tumors were positive for G12D, 20% for G12V, and 10% for G12C. One tumor was positive for G12D and G12V. Analysis of the mutations in matched plasma samples revealed detection rates of 36% for G12D, 50% for G12V, and 0% for G12C. The detection appeared to be correlated with total number of tumor cells in the primary tumor. No KRAS mutations were detected in 20 samples of healthy control plasma. CONCLUSIONS Our results support further evaluation of tumor specific mutations as early diagnostic biomarkers using plasma samples as liquid biopsy.

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CLO21-012: Isolation and Characterization of Circulating Tumor DNA to Monitor Acute Lymphoblastic Leukemia

Journal of the National Comprehensive Cancer Network ◽

10.6004/jnccn.2020.7764 ◽

2021 ◽

Vol 19 (3.5) ◽

pp. CLO21-012

Author(s):

Thomas Lee Amburn ◽

Meghan Haney ◽

Henry Moore ◽

Tom Badgett ◽

Jessica Blackburn

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Lymphoblastic Leukemia ◽

Circulating Tumor Dna ◽

Isolation And Characterization ◽

Tumor Dna

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Erratum to: PNA clamping-assisted fluorescence melting curve analysis for detecting EGFR and KRAS mutations in the circulating tumor DNA of patients with advanced non-small cell lung cancer

BMC Cancer ◽

10.1186/s12885-016-2760-9 ◽

2016 ◽

Vol 16 (1) ◽

Author(s):

Ji-Youn Han ◽

Jae-Jin Choi ◽

Jin Young Kim ◽

You Lim Han ◽

Geon Kook Lee

Keyword(s):

Lung Cancer ◽

Melting Curve ◽

Circulating Tumor Dna ◽

Small Cell ◽

Curve Analysis ◽

Melting Curve Analysis ◽

Small Cell Lung ◽

Kras Mutations ◽

Fluorescence Melting Curve Analysis ◽

Tumor Dna

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Ultra-low Input Circulating Tumor DNA Detection by MED-Amp in Early-Stage Pancreatic Cancer

10.1101/2021.03.28.437388 ◽

2021 ◽

Author(s):

Erica D Pratt ◽

David B Zhen ◽

Robert W Cowan ◽

Heather Cameron ◽

Kara Schradle ◽

...

Keyword(s):

Early Stage ◽

Locally Advanced ◽

Progression Free Survival ◽

Circulating Tumor Dna ◽

Fold Change ◽

Diagnostic Sensitivity ◽

Ductal Adenocarcinoma ◽

Kras Mutations ◽

The Relationship ◽

Tumor Dna

Purpose: The clinical utility of circulating tumor DNA (ctDNA) has been shown in advanced pancreatic ductal adenocarcinoma (PDA). However, diagnostic sensitivity of many ctDNA assays is low in resectable and locally advanced disease, where tumor burden is substantially lower. We have previously described Multiplex Enrichment using Droplet Pre-Amplification (MED-Amp), a multiplexed panel for the detection of the most common oncogenic KRAS mutations in PDA. In this study, we aimed to assess the diagnostic sensitivity of MED-Amp for detection of rare mutant alleles present in the plasma of patients with localized PDA. Experimental Design: We retrospectively analyzed ninety-eight plasma samples from 51 patients with various stages of localized disease. For comparison, we measured ctDNA levels in 20 additional patients with metastatic PDA. The MED-Amp assay was used to measure the abundance of the four most common KRAS codon 12 mutations (G12C/D/R/V). We correlated the presence and quantity of ctDNA with overall survival (OS) as well as progression-free survival (PFS). Using serial plasma draws, we also assessed the relationship between changes in ctDNA allelic frequency and progression. Results: KRAS-positive ctDNA was detected in 52.9% of localized PDA and 75% of metastatic samples tested using DNA inputs as low as 2 ng. As previously reported, the presence of KRAS mutant ctDNA was correlated with worse OS for all disease stages (p = 0.02). In patients with localized PDA high ctDNA levels also correlated with significantly worse median OS (533 days vs 1090 days) and PFS (192 days vs 787 days). We also studied a small cohort of serial plasma draws to observe the relationship between ctDNA fold change and PFS. We found 83% of patients with increased fold change in mutant KRAS experienced disease progression (n=6). In contrast, 75% (n=4) of patients with decreased fold change remained disease-free (p=0.03). Conclusions: MED-Amp is a flexible and cost-effective approach for measurement of ctDNA in patients with localized cancer. Though this study focused on KRAS mutation detection, this assay could be adapted for a number of common oncogenic alterations.

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