Pancreatic cancer is the fourth leading cause of cancer deaths in the United States, and pancreatic cancer has some of the lowest 5-year survival rates of any cancer. Early detection can improve survival rates. When pancreatic ductal adenocarcinoma is initially diagnosed at stage IV, patients have a 2.7% 5-year survival rate. When diagnosis occurs at Stage I or IIA, this improves to 34%. However, there are currently no accurate blood tests for early detection of pancreatic cancer. Cancer cells secrete exosomes that contain microRNAs, and these microRNAs provide a snapshot of the altered activity of cancer cells compared to normal cells. A group led by Wei-Qun Ding, PhD tested whether exosomal microRNAs can be used to identify pancreatic cancer.
The authors first compared exosomal microRNAs from pancreatic cancer cells lines to exosomal microRNAs from other cell lines. Pancreatic cancer cell lines had higher levels of 30 exosomal microRNAs, and three exosomal microRNAs were selectively expressed in pancreatic cancer cell lines. Next, the authors tested whether these three exosomal microRNAs were also present in the blood of patients with early pancreatic cancer (stage I or stage IIA). Compared to individuals without pancreatic cancer, patients with early pancreatic cancer had higher blood levels of two of the exosomal microRNAs, called miR196a and miR-1246. On average, patients with pancreatic ductal adenocarcinoma had higher levels of miR-196a, and patients with intraductal papillary mucinous neoplasms had higher levels of both miR-196a and miR-1246. However, neither of these exosomal microRNAs were elevated in patients with well differentiated neuroendocrine tumors. These results suggest that blood levels of exosomal microRNAs could be useful as a novel tool for early detection of pancreatic cancer.
This study was funded by an OSCTR pilot grant. As an OSCTR pilot investigator, the project PI has mentoring, professional development, and training resources from the OSCTR. In addition, the OSCTR Clinical Resources core provided assistance with regulatory issues, recruited the patients for this study, and helped obtain samples. The OSCTR Biostatistics, Epidemiology, and Research Design Core contributed to the statistical design and analysis of the study, and a member of that core is also a co-author of the manuscript.
Reference: Xu YF, Hannafon BN, Zhao YD, Postier RG, Ding WQ. Plasma Exosome miR-196a and miR-1246 Are Potential Indicators of Localized Pancreatic Cancer. Oncotarget. 2017 Aug 18;8(44):77028-77040.https://pubmed.ncbi.nlm.nih.gov/29100367/