PRELIMINARY STUDY ANALYZING THE METHYLATED GENES IN THE PLASMA OF PATIENTS WITH PANCREATIC CANCER

Background and Aims: CpG islands of the promoter region of some genes are methylated in pancreatic cancer tissue and the detection of this methylation has been suggested to be useful in the diagnosis of various cancers. The aim of this study was to investigate whether the detection of methylated CpG islands in plasma can be used in the diagnosis of pancreatic cancer. Material and Methods: Plasma DNA was collected from patients with pancreatic cancer, chronic pancreatitis, and healthy controls. The methylation status of six genes, UCHL1, NPTX2, SARP2, ppENK, p16, and RASSF1A, was checked by methylation-specific PCR and was subsequently confirmed by direct sequencing after bisulfite treatment. Results: CpG island methylation was detectable in 13 of 16 patients (81.3%) with pancreatic cancer, 1 of 29 healthy controls (3.5%), and 8 of 13 patients with chronic pancreatitis (61.5%). The mean number of genes with CpG island methylation was 1.6 +/- 1.2 in pancreatic cancer, 0.04 +/- 0.19 in healthy controls, and 1.2 +/- 1.1 in chronic pancreatitis. Among six genes, p16 was more specifically methylated in pancreatic cancer compared with chronic pancreatitis (p = 0.016). The methylation status was not correlated with smoking history, tumor size, or cancer stage. Conclusions: The detection of methylated genes in the plasma may have a role in differentiating between pancreatic cancers and healthy controls but not between pancreatic cancer and chronic pancreatitis.