BioProject

Formalin-fixed, paraffin-embedded (FFPE) archival tissue is an important source of DNA material. More...

Formalin-fixed, paraffin-embedded (FFPE) archival tissue is an important source of DNA material. The most commonly used technique to identify copy number aberrations from chromosomal DNA in tumorigenesis is array comparative genomic hybridization (aCGH). Although copy number analysis using DNA from FFPE archival tissue is challenging, several research groups have reported high quality and reproducible DNA copy number results using aCGH. Aim of the present study is to compare aCGH platforms suitable for copy number analysis using FFPE derived DNA. Two dual channel aCGH platforms (Agilent and NimbleGen) and a single channel SNP based platform (Affymetrix), were evaluated using seven FFPE colon cancer samples, median absolute deviation (MAD), deflection, signal-to-noise ratio (SNR) and DNA input requirements were used as quality criteria. Large differences were observed in MAD values and deflection between platforms; Agilent and NimbleGen showed better MAD values (0.13 for both) compared to Affymetrix (0.22). Contrary, Affymetrix showed a better deflection of 0.94, followed by 0.71 for Agilent and 0.51 for NimbleGen. Since the deflection compensates for the MAD the Signal to Noise Ratios (SNR) were comparable; Agilent ranks first, Affymetrix second and NimbleGen third with SNRs of 3.9, 3.6 and 3.3 respectively. DNA input amounts of 40ng are sufficient for high quality profiles with Affymetrix. For Agilent DNA input amounts of 50ng are sufficient for high quality profiles. For results of similar quality NimbleGen requires at least 100ng. Copy number analysis using DNA derived from FFPE archival material is feasible and shows reproducible results on high-resolution copy number platforms. Input amounts of DNA from FFPE material lower than recommended still yield high quality profiles without additional amplification steps. Overall design: Overall study comprises 6 samples analyzed across three platforms with an additional dilution range (5 concentrations) of a seventh sample on two platforms. This Series represents NimbleGen platform-derived data. Less...