Detection of K-ras gene mutations at codon 12 in the pancreatic juice of patients with intraductal papillary mucinous tumors of the pancreas

Detection of mutant KRAS and TP53 DNA in circulating exosomes from healthy individuals and patients with pancreatic cancer

Pancreatic cancer presents with a dismal mortality rate and is in urgent need of methods for early detection with potential for timely intervention. All living cells, including cancer cells, generate exosomes. We previously discovered double stranded genomic DNA in exosomes derived from the circulation of pancreatic cancer patients, which enabled the detection of prevalent mutations associated with the disease. Here, we report a proof-of-concept study that demonstrates the potential clinical utility of circulating exosomal DNA for identification of KRAS^G12D and TP53^R273H mutations in patients with pancreas-associated pathologies, including pancreatic ductal adenocarcinoma (PDAC), chronic pancreatitis (CP) and intraductal papillary mucinous neoplasm (IPMN), and in healthy human subjects. In 48 clinically annotated serum samples from PDAC patients, digital PCR analyses of exosomal DNA identified KRAS^G12D mutation in 39.6% of cases, and TP53^R273H mutation in 4.2% of cases. KRAS^G12D and TP53^R273H mutations were also detected in exosomal DNA from IPMN patients (2 out of 7 with KRAS^G12D, one of which also co-presented with TP53^R273H mutation). Circulating exosomal DNA in 5 out of 9 CP patients enabled the detection of KRAS^G12D mutation. In 114 healthy subject-derived circulating exosomal DNA, 2.6% presented with KRAS^G12D mutation and none with TP53^R273H mutation. This study highlights the value of circulating exosomal DNA for a rapid, low-cost identification of cancer driving mutations. The identification of mutations in IPMN patients and healthy subjects suggests that liquid biopsies may allow potential assessment of cancer risk but with a cautionary note that detection of clinical cancer cannot be assumed.

Advances in pancreatitic intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) are a well-characterized group of intraductal mucin-producing cystic neoplasms of pancreas with clear malignant potential. It has a favorable prognosis and distinct molecular or clicinopathologic features compared with other types of pancreatic tumors. In addition, IPMNs can be divided into several subtypes in accordance with the papillary structure and mucin expression profile. Importantly, as IPMNs are acknowledged as key stages during pancreatic carcinogenesis, it can better reveal the mechanism and biological characteristics of IPMNs through further investigation of the pathologic features and the molecular aberrations harbored in different subtypes of IPMNs. This paper reviewed relevant literatures and elucidated its progression in terms of the molecular and clicinopathologic characteristics, diagnosis, treatment and prognosis of IPMNs.