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Comparison of KRAS Mutation Assessment in Tumor DNA and Circulating Free DNA in Plasma and Serum Samples.

Morgan SR, Whiteley J, Donald E, Smith J, Eisenberg MT, Kallam E, Kam-Morgan L - Clin Med Insights Pathol (2012)

Bottom Line: This study assessed the identification of KRAS mutations in circulating free DNA (cfDNA) using a commercially available KRAS polymerase chain reaction (PCR) kit.Yields of cfDNA from plasma and serum samples were comparable.Analyses were successful in 70/71 plasma-extracted samples (specificity: 97%, sensitivity: 31%) and 67/71 serum- extracted samples (specificity: 100%, sensitivity: 25%).

View Article: PubMed Central - PubMed

Affiliation: AstraZeneca, Alderley Park, Macclesfield, Cheshire, UK.

ABSTRACT
Testing for mutations in the KRAS oncogene for patients with metastatic colorectal cancer (mCRC) is generally performed using DNA from formalin-fixed paraffin-embedded tumor tissue; however, access to specimens can be limited and analysis challenging. This study assessed the identification of KRAS mutations in circulating free DNA (cfDNA) using a commercially available KRAS polymerase chain reaction (PCR) kit. Matched plasma, serum and tumor samples were available from 71 patients with mCRC who had received prior therapy but whose disease progressed following therapy. Yields of cfDNA from plasma and serum samples were comparable. Analyses were successful in 70/71 plasma-extracted samples (specificity: 97%, sensitivity: 31%) and 67/71 serum- extracted samples (specificity: 100%, sensitivity: 25%). This study demonstrates that KRAS mutations can be detected in cfDNA using a commercially available KRAS PCR kit, confirming cfDNA as a potential alternative source of tumor DNA in a diagnostic setting if access to archival tumor specimens is limited.

No MeSH data available.


Related in: MedlinePlus

Mutation threshold cycle (Ct) values in plasma- and serum-extracted cfDNA samples.
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Related In: Results  -  Collection


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f2-cpath-5-2012-015: Mutation threshold cycle (Ct) values in plasma- and serum-extracted cfDNA samples.

Mentions: Matched plasma and serum samples were available from 71 patients with analyzed FFPE tumor samples; for the remaining 38 patients the amount of plasma and serum available was insufficient for cfDNA extraction. Control Ct values for plasma- and serum-extracted cfDNA samples, which are indicative of the total DNA yields, were similar (mean: 31.93 and 31.35; range 24 to 35 and 28 to 35, respectively; Figure 2). Mutations of KRAS continued to be detected when control Ct values were high, suggesting that mutations can still be detected even when the overall DNA yield is low (Fig. 2). Average ΔCt values were lower in plasma samples than serum samples, suggesting that the mutation load in plasma was higher (Fig. 2).


Comparison of KRAS Mutation Assessment in Tumor DNA and Circulating Free DNA in Plasma and Serum Samples.

Morgan SR, Whiteley J, Donald E, Smith J, Eisenberg MT, Kallam E, Kam-Morgan L - Clin Med Insights Pathol (2012)

Mutation threshold cycle (Ct) values in plasma- and serum-extracted cfDNA samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3362326&req=5

f2-cpath-5-2012-015: Mutation threshold cycle (Ct) values in plasma- and serum-extracted cfDNA samples.
Mentions: Matched plasma and serum samples were available from 71 patients with analyzed FFPE tumor samples; for the remaining 38 patients the amount of plasma and serum available was insufficient for cfDNA extraction. Control Ct values for plasma- and serum-extracted cfDNA samples, which are indicative of the total DNA yields, were similar (mean: 31.93 and 31.35; range 24 to 35 and 28 to 35, respectively; Figure 2). Mutations of KRAS continued to be detected when control Ct values were high, suggesting that mutations can still be detected even when the overall DNA yield is low (Fig. 2). Average ΔCt values were lower in plasma samples than serum samples, suggesting that the mutation load in plasma was higher (Fig. 2).

Bottom Line: This study assessed the identification of KRAS mutations in circulating free DNA (cfDNA) using a commercially available KRAS polymerase chain reaction (PCR) kit.Yields of cfDNA from plasma and serum samples were comparable.Analyses were successful in 70/71 plasma-extracted samples (specificity: 97%, sensitivity: 31%) and 67/71 serum- extracted samples (specificity: 100%, sensitivity: 25%).

View Article: PubMed Central - PubMed

Affiliation: AstraZeneca, Alderley Park, Macclesfield, Cheshire, UK.

ABSTRACT
Testing for mutations in the KRAS oncogene for patients with metastatic colorectal cancer (mCRC) is generally performed using DNA from formalin-fixed paraffin-embedded tumor tissue; however, access to specimens can be limited and analysis challenging. This study assessed the identification of KRAS mutations in circulating free DNA (cfDNA) using a commercially available KRAS polymerase chain reaction (PCR) kit. Matched plasma, serum and tumor samples were available from 71 patients with mCRC who had received prior therapy but whose disease progressed following therapy. Yields of cfDNA from plasma and serum samples were comparable. Analyses were successful in 70/71 plasma-extracted samples (specificity: 97%, sensitivity: 31%) and 67/71 serum- extracted samples (specificity: 100%, sensitivity: 25%). This study demonstrates that KRAS mutations can be detected in cfDNA using a commercially available KRAS PCR kit, confirming cfDNA as a potential alternative source of tumor DNA in a diagnostic setting if access to archival tumor specimens is limited.

No MeSH data available.


Related in: MedlinePlus