The aim of the study is to evaluate whether peripheral circulating cell-free tumor DNA(ctDNA) can help early screening of pancreatic cancer recurrence or not. And we are also planning to evaluate correlation between ctDNA with clinical outcome of pancreatic cancer.

In the formation and growth of a primary tumor, cells can released into the bloodstream. There are many researches for these circulating tumor cells(CTC) And recently circulating cell-free tumor DNA(ctDNA) released from apoptotic or necrotic tumor cells has developed. At one report which checked ctDNA level after operation of colon cancer patients, they suggested that ctDNA could show recurrence of cancer several months earlier than the conventional follow up imaging. And several reports suggested that ctDNA can invade host cell and change host cell biology, which can evoke cancer metastasis.

So in this study, the investigator will collect ctDNA of pancreatic cancer patients, benign pancreatic disease patients, and healthy population. And the investigator will evaluate whether peripheral ctDNA can help early screening of cancer recurrence. And we will study about genomic signature of ctDNA to evaluate relationship between ctDNA and clinical outcome of cancer patients.

Inclusion Criteria:

• Comparative group : Pancreatic cancer patients who progress endoscopic ultrasonography fine-needle aspiration (EUS-FNA) for pancreatic cancer diagnosis, pancreatic cancer patients who are in operable stage
• Control group : Benign pancreas disease patients who progress EUS-FNA for diagnosis, healthy population

Exclusion Criteria:

• Foreigners
• Pancreatic cancer patients who have other cancer
• Patients who impossible to consent to study by own

Consecutive pancreatic cancer patients who received EUS-FNA for diangosis and undergo operation, benign pancreas disease patients who received EUS-FNA for diagnosis, healthy population