FFPE study using MIP copy number platform - liver

: A major challenge to the study of tumor DNA copy number (CN) in clinical specimens is the lack of appropriate fresh frozen samples and thus a dependence on Formalin-Fixed Paraffin Embedded (FFPE) banked samples, which typically have more extensive clinical follow up information. However, on most high density CN platforms, DNA from FFPE tissues generally underperforms or suffers high failure rates compared to fresh frozen samples because of DNA degradation and cross-linking. Molecular Inversion Probe (MIP) technology has been applied successfully to obtain high quality CN and genotype data from DNA isolated from cell lines and frozen tumor samples. Since the MIP probes require only a small (~40 bp) target binding site, we reasoned they may be well suited to assess FFPE samples. In this study, we successfully applied MIP technology with a panel of 50,000 markers to CN determination in FFPE samples. Using an input of 37 ng genomic DNA, we demonstrated high quali ty CN data with MIP technology from 93 FFPE samples from seven diverse collections. We found that the performance of FFPE DNA for CN determination was comparable to that of DNA obtained from matched frozen tumor, with only a modest loss in performance of DNA. Various collections of FFPE samples have been assayed by MIP