KRAS Mutation Detection in Paired Frozen and Formalin-Fixed Paraffin-Embedded (FFPE) Colorectal Cancer Tissues.

Author(s): Solassol J, Ramos J, Crapez E, Saifi M, Mangé A, Vianès E, Lamy PJ, Costes V, Maudelonde T

Publication: Int J Mol Sci, 2011, Vol. 12, Page 3191-204

PubMed ID: 21686179 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to compare KRAS mutation status in FFPE and frozen colorectal tumors. Each specimen was cut into two pieces, 1 of which was snap-frozen in liquid nitrogen and the other was processed for FFPE. DNA was extracted using the QIAamp kit from both types of specimens.

   Summary of Findings:

   DNA yield was similar from FFPE and frozen specimens, but FFPE specimens had higher average cycle threshold (CT) values and a larger range in CT values. Using 33 FFPE specimens with a known KRAS mutation determined using the matched frozen specimen, HRM missclassified 2 (6%) as wildtype, and 2 others did not amplify properly. After sequencing, 6 (18%) FFPE specimens were missclassified as wildtype, and 3 (9.1%) showed mutations not identified using the corresponding frozen specimen. Of the 68 FFPE specimens that did not have a KRAS mutation identified using the matched frozen specimen, all were genotyped as wildtype, but in 4 cases, DNA failed to amplify.

   Biospecimens

   • Tissue - Colorectal

   Preservative Types

   • Formalin
   • Frozen

   Diagnoses:

   • Neoplastic - Carcinoma

   Platform:

   Analyte	Technology Platform
   DNA	Spectrophotometry
   DNA	Real-time qPCR
   DNA	DNA sequencing
   DNA	SNP assay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Type of fixation/preservation	Formalin (buffered) Snap frozen
   SNP assay Specific	Targeted nucleic acid	KRAS
   SNP assay Specific	Technology platform	HRM Sequencing

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