Adenocarcinoma is a type of cancer that occurs in the glandular cells throughout the body. There are several metastatic adenocarcinoma of unknown primary origin. Currently, there is no highly effective method to differentiate pancreatic ductal adenocarcinoma (PDAC) from other adenocarcinomas. Here, we identified pancreas tissue by site-specific methylation at FRY and found that it can also detect PDAC. The establishment of Combined Bisulphite Restriction Analysis (COBRA) and quantitative real-time PCR techniques of FRY revealed FRY hypermethylation in 21 out of 24 normal pancreatic tissue samples, whereas all other normal tissue samples from thirteen other organs (80 samples) remained totally unmethylated. Similarly in application to PDAC, this marker effectively indicated 25 PDAC among 151 other common adenocarcinomas with values of 100%, 98.7%, 92.6%, and 100% in sensitivity, specificity, positive predictive value and negative predictive value, respectively. In summary, we have demonstrated that this epigenetic site-specific marker has high potential for pancreatic tissue identification and can be applied in PDAC diagnosis.