Diagnosis and Prognostication of Ductal Adenocarcinomas of the Pancreas Based on Genome-Wide DNA Methylation Profiling by Bacterial Artificial Chromosome Array-Based Methylated CpG Island Amplification
Figure 1
Genome-wide DNA methylation analysis by BAMCA. (a) Representative examples of scanned array images in a sample of normal pancreatic tissue obtained from a patient without ductal adenocarcinoma of the pancreas (C) and samples of both noncancerous pancreatic tissue (N) and cancerous tissue (T) obtained from a single patient with ductal adenocarcinoma of the pancreas. Test and reference DNA labeled with Cy3 and Cy5 was cohybridized, respectively. (b) Representative examples of scattergrams of the signal ratios (test signal/ reference signal) in each C-, N-, and T-sample. In all C-samples, the signal ratios of 97% of the BAC clones were between 0.67 and 1.5 (red lines). Therefore, in N- and T samples, DNA methylation status corresponding to a signal ratio of less than 0.67 and more than 1.5 was defined as DNA hypo- and hypermethylation on each BAC clone relative to C-samples, respectively. In N-samples, many BAC clones showed DNA hypo- or hypermethylation. In T-samples, more BAC clones showed DNA hypo- or hypermethylation, and the degree of DNA hypo- or hypermethylation, that is, deviation of the signal ratio from 0.67 or 1.5, was increased in comparison with N-samples.
