Notes: DNA was purified from 46 carcinoma FFPE blocks using the same method that was used ~5.5 years after the samples were originally studied. The purified DNA was quantified and showed on average a 53% decline in the amount of DNA recovered from each sample. Amplifiability of purified DNA over time was determined by the ProNex® DNA QC Assay. ProNex® DNA QC Assay results showed that length of amplifiable DNA fragments decreased over time by comparing the ratio of 75bp fragments to 150bp and 300bp fragments respectively. The ratio of 75bp to 150bp fragments showed a decrease in amplifiable DNA from 58% to 16% over time, while the ratio of 75bp to 300bp fragments showed a decrease in amplifiable DNA from 31% to 2%. The decrease in amplifiable DNA fragments lead to a 3.3 fold decrease in library preparation yield. (4879)