Gradual telomere shortening in the tumorigenesis of pancreatic and hepatic mucinous cystic neoplasms

Mucinous cystic neoplasm (MCN) is one of the precursor lesions of pancreatic ductal adenocarcinoma and intrahepatic cholangiocarcinoma. The aim of this study is to examine the presence of short telomeres in promoting the tumorigenesis of MCN by measuring telomere lengths in distinct components of MCN, including the mucinous lining epithelium, non-mucinous lining epithelium, and ovarian-type stroma. A total of 45 patients with MCN (30 pancreatic and 15 hepatic cases) were obtained. Quantitative telomere-specific fluorescent in situ hybridization was performed to measure the telomere length of specific cell types within MCNs, including mucinous lining epithelium, non-mucinous lining epithelium, and ovarian-type stroma, as well as normal ductal epithelium and adenocarcinoma. Relative telomere lengths tended to decrease between normal ductal epithelium, ovarian-type stroma, non-mucinous lining epithelium, mucinous lining epithelium, and adenocarcinoma regardless of the involved organs. Among the analyzed cell types, relative telomere lengths were significantly different between normal ductal epithelium (3.31 ± 0.78), ovarian-type stroma (2.90 ± 0.93), non-mucinous lining epithelium (2.84 ± 0.79), mucinous lining epithelium (2.49 ± 0.93), and adenocarcinoma (1.19 ± 0.59), respectively (P < 0.001, mixed-effects model). As expected, no difference in relative telomere lengths was observed between normal ductal epithelium and ovarian-type stroma; however, significant differences were observed in pair-wise comparisons between ovarian-type stroma vs. non-mucinous lining epithelium (P = 0.001), non-mucinous lining epithelium vs. mucinous lining epithelium (P = 0.005), and mucinous lining epithelium vs. adenocarcinoma (P < 0.001). These findings suggest gradual telomere shortening occurs in the tumorigenesis of MCN, which may have important implications for the progression of this disease.