Differential Identification of Pancreatic Cysts

Abstract

More than 2% of adults harbor a pancreatic cyst, a subset of which progress to invasive lesions with lethal consequences. To assess the genomic landscapes of neoplastic cysts of the pancreas, we determined the exomic sequences of DNA from the neoplastic epithelium of eight surgically resected cysts of each of the major neoplastic cyst types: serous cystadenomas (SCAs), intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs) and solid pseudo-papillary neoplasms (SPNs). SPNs are low-grade malignancies, and IPMNs and MCNs, but not SCAs, have the capacity to progress to cancer. We found that SCAs, IPMNs, MCNs, and SPNs contained 10=4.6, 27=12, 16=7.6, and 2.9=2.1 somatic mutations per tumor, respectively. Among the mutations identified, E3 ubiquitin ligase components were of particular note. Four of the eight SCAs contained mutations of VHL, a key component of the VHL ubiquitin ligase complex that has previously been associated both with renal cell carcinomas, SCAs, and other neoplasms. Six of the eight IPMNs and three of the eight MCNs harbored mutations of RNF43, a gene coding for a protein with intrinsic E3 ubiquitin ligase activity that has not previously been found to be genetically altered in any human cancer. The preponderance of inactivating mutations in RNF43 unequivocally establish it as a suppressor of both IPMNs and MCNs. SPNs contained remarkably few genetic alterations, but always contained mutations of CTNNB1, previously demonstrated to inhibit degradation of the encoded protein (β-catenin) by E3 ubiquitin ligases. These results highlight the essential role of ubiquitin ligases in these neoplasms and have important implications for the diagnosis and treatment of patients with cystic tumors.

Description

[0001]The invention was made with government support under CA 62924, CA 57345, and CA 43460 awarded by National Institutes of Health. The government has certain rights in the invention.TECHNICAL FIELD OF THE INVENTION[0002]This invention is related to the area of cancer management. In particular, it relates to the areas of prognosis and diagnosis.BACKGROUND OF THE INVENTION[0003]As the result of the increasing use of abdominal imaging in standard medical practice, pancreatic cysts are being identified with increasing frequency. Management of these cysts is concomitantly becoming a major clinical problem (1, 2). These lesions occur in more than 20% of patients examined at autopsy (3), in as many as 19.6% of patients evaluated by MRI (4-6), and as many as 2.6% of patients evaluated by CT (7, 8). In the vast majority of cases, the cysts are identified as incidental findings in patients undergoing imaging for symptoms unrelated to pancreatic pathology. But once a cyst is identified, it ...

AI Technical Summary

Benefits of technology

The invention provides methods and tools to differentially diagnose pancreatic cysts based on the mutations in certain genes. This method can identify the type of pancreatic cyst, such as serous cystadenoma or mucinous cystic neoplasm, and aid in managing medical treatment. The methods involve testing the nucleic acids isolated from cyst fluid or epithelial cells and detecting mutations in genes like VHL, GNAS, RNF43, KRAS, and CTNNB1. A device or kit can also be used for this purpose. Overall, the invention helps in better understanding and managing pancreatic cysts.

Problems solved by technology

Management of these cysts is concomitantly becoming a major clinical problem (1, 2).

But once a cyst is identified, it poses a challenging, life-long management problem (1, 2, 9-13).

Unfortunately, it is often difficult to determine the type of cyst from conventional clinical, radiographic, or cytologic findings (1, 2, 9-16, 17)

The pre-operative diagnosis of surgically-excised cysts has been shown to be erroneous in one third of cases, which can lead to unnecessary surgical procedures (22).

These fluids are often acellular and therefore not typically useful for cytologic diagnosis.

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