SERPINB5 and AKAP12 -- Expression and promoter methylation of metastasis suppressor genes in pancreatic ductal adenocarcinoma

<p>Abstract</p> <p>Background</p> <p>Early metastasis and infiltration are survival limiting characteristics of pancreatic ductal adenocarcinoma (PDAC). Thus, PDAC is likely to harbor alterations in metastasis suppressor genes that may provide novel diagnostic and therapeutic opportunities. This study investigates a panel of metastasis suppressor genes in correlation to PDAC phenotype and examines promoter methylation for regulatory influence on metastasis suppressor gene expression and for its potential as a diagnostic tool.</p> <p>Methods</p> <p>Metastatic and invasive potential of 16 PDAC cell lines were quantified in an orthotopic mouse model and mRNA expression of 11 metastasis suppressor genes determined by quantitative RT-PCR. Analysis for promoter methylation was performed using methylation specific PCR and bisulfite sequencing PCR. Protein expression was determined by Western blot.</p> <p>Results</p> <p>In general, higher metastasis suppressor gene mRNA expression was not consistent with less aggressive phenotypes of PDAC. Instead, mRNA overexpression of several metastasis suppressor genes was found in PDAC cell lines vs. normal pancreatic RNA. Of the investigated metastasis suppressor genes, only higher <it>AKAP12 </it>mRNA expression was correlated with decreased metastasis (P < 0.05) and invasion scores (P < 0.01) while higher <it>SERPINB5 </it>mRNA expression was correlated with increased metastasis scores (P < 0.05). Both genes' promoters showed methylation, but only increased <it>SERPINB5 </it>methylation was associated with loss of mRNA and protein expression (P < 0.05). <it>SERPINB5 </it>methylation was also directly correlated to decreased metastasis scores (P < 0.05).</p> <p>Conclusions</p> <p><it>AKAP12 </it>mRNA expression was correlated to attenuated invasive and metastatic potential and may be associated with less aggressive phenotypes of PDAC while no such evidence was obtained for the remaining metastasis suppressor genes. Increased <it>SERPINB5 </it>mRNA expression was correlated to increased metastasis and mRNA expression was regulated by methylation. Thus, <it>SERPINB5 </it>methylation was directly correlated to metastasis scores and may provide a diagnostic tool for PDAC.</p

Whole exome sequencing reveals recurrent mutations in BRCA2 and FAT genes in acinar cell carcinomas of the pancreas

Acinar cell carcinoma of the pancreas is a rare tumor with a poor prognosis. Compared to pancreatic ductal adenocarcinoma, its molecular features are poorly known. We studied a total of 11 acinar cell carcinomas, including 3 by exome and 4 by target sequencing. Exome sequencing revealed 65 nonsynonymous mutations and 22 indels with a mutation rate of 3.4 mutations/Mb per tumor, on average. By accounting for not only somatic but also germline mutations with loss of the wild-type allele, we identified recurrent mutations of BRCA2 and FAT genes. BRCA2 showed somatic or germline premature termination mutations, with loss of the wild-type allele in 3 of 7 tumors. FAT1, FAT3, and FAT4 showed somatic or germline missense mutations in 4 of 7 tumors. The germline FAT mutations were with loss of the wild-type allele. Loss of BRCA2 expression was observed in 5 of 11 tumors. One patient with a BRCA2-mutated tumor experienced complete remission of liver metastasis following cisplatinum chemotherapy. In conclusion, acinar cell carcinomas show a distinct mutation pattern and often harbor somatic or germline mutations of BRCA2 and FAT genes. This result may warrant assessment of BRCA2 abrogation in patients with the carcinoma to determine their sensitivity to chemotherapy

Pancreatic Neuroendocrine Tumors: Update on the New World Health Organization Classification

The first classification of the pancreatic neuroendocrine neoplasms (PanNENs) that characterized the individual tumor by criteria with prognostic significance appeared in 1995. These criteria included a distinction by site and size, by degree of histological differentiation (well vs poor), by function (with and without hormonal syndrome), by angioinvasion, and by metastatic spread. The subsequently developed World Health Organization classifications in 2000, 2004, and 2010 largely followed this concept, but added proliferative activity as the best criterion reflecting tumor growth. In 2010, the classification combined histological differentiation with stratification into 3 tiers of proliferative activity, mainly using Ki67 as the most reliable measure of proliferation. The predictive value of this classification and grading system that was soon accompanied by an adequate TNM staging system has proved to be so excellent that all major treatment options of PanNENs, as well as extrapancreatic NENs, have been currently based on this classification. The new World Health Organization 2017 classification is a refinement of the previous version. Its main change is the introduction of a “pancreatic neuroendocrine tumor grade 3” category to recognize grade-discordant pancreatic neuroendocrine tumors and distinguish them from pancreatic neuroendocrine carcinomas, which are defined by their poorly differentiated nature. There is increasing evidence that this phenotypical classification of PanNENs allows a targeted molecular analysis, which is going to broaden our understanding of the tumors' biology

Prognostic relevance of morphological types of intraductal papillary mucinous neoplasms of the pancreas

Objective: The clinicopathological significance of four morphological types of intraductal papillary mucinous neoplasms of the pancreas (IPMNs; gastric, intestinal, pancreatobiliary and oncocytic) was assessed. Design Retrospective multicentre analysis of 283 surgically resected IPMNs. Results: Of the 283 IPMNs, 139 were of the gastric type, 101 were intestinal, 19 were pancreatobiliary and 24 were oncocytic. These types were significantly associated with clinicopathological factors including sex (p=0.0032), age (p=0.00924), ectatic duct size (p=0.0245), detection of mural nodules (p=4.09×10−6), histological grade (p<2.20×10−16), macroscopic types with differential involvement of the pancreatic duct system (p=3.91×10−5), invasive phenotypes (p=3.34×10−12), stage (p<2.20×10−16) and recurrence (p=0.00574). Kaplan–Meier analysis showed significant differences in patient survival by morphological type (p=5.24×10−6). Survival rates at 5 and 10 years, respectively, were 0.937 (95% CI 0.892 to 0.984) for patients with gastric-type IPMNs; 0.886 (95% CI 0.813 to 0.965) and 0.685 (95% CI 0.553 to 0.849) for those with intestinal-type IPMNs; 0.839 (95% CI 0.684 to 1.000) and 0.734 (95% CI 0.526 to 1.000) for those with oncocytic-type IPMNs; and 0.520 (95% CI 0.298 to 0.909) and undetermined for those with pancreatobiliary-type IPMNs. Analysis by the Cox proportional hazards model comparing prognostic risks determined by stage and the morphological and macroscopic types indicated that staging was the most significant predictor of survival (p=3.68×10−8) followed by the morphological type (p=0.0435). Furthermore, the morphological type remained a significant predictor in a subcohort of invasive cases (p=0.0089). Conclusion: In this multicentre retrospective analysis, the morphological type of IPMN appears to be an independent predictor of patient prognosis