Purpose: We investigated the global gene expression in a large panel of pancreatic endocrine tumors (PETs) aimed at identifying new potential targets for therapy and biomarkers to predict patient outcome. Patients and Methods: Using a custom microarray, we analyzed 72 primary PETs, seven matched metastases, and 10 normal pancreatic samples. Relevant differentially expressed genes were validated by either quantitative real-time polymerase chain reaction or immunohistochemistry on tissue microarrays. Results: Our data showed that: tuberous sclerosis 2 (TSC2) and phosphatase and tensin homolog (PTEN) were downregulated in most of the primary tumors, and their low expression was significantly associated with shorter disease-free and overall survival; somatostatin receptor 2 (SSTR2) was absent or very low in insulinomas compared with nonfunctioning tumors; and expression of fibroblast growth factor 13 (FGF13) gene was significantly associated with the occurrence of liver metastasis and shorter disease-free survival. TSC2 and PTEN are two key inhibitors of the Akt/mammalian target of rapamycin (mTOR) pathway and the specific inhibition of mTOR with rapamycin or RAD001 inhibited cell proliferation of PET cell lines. Conclusion: Our results strongly support a role for PI3K/Akt/mTOR pathway in PET, which ties in with the fact that mTOR inhibitors have reached phase III trials in neuroendocrine tumors. The finding of differential SSTR expression raises the potential for SSTR expression to be evaluated as a marker of response to somatostatin analogs. Finally, we identified FGF13 as a new prognostic marker that predicted poorer outcome in patients who were clinically considered free from disease.

The pathogenetic mechanisms behind gastric cancer are still unclear. Its familial aggregation, on the other hand, has been very well documented by many epidemiologists. Nonetheless, only a limited number of studies have analyzed possible correlations between demographic and clinical data.

PIK3CA is one of the genes most frequently mutated in human cancers and it is a potential target for personalized therapy. The aim of this study was to assess the frequency and type of PIK3CA mutations in gastric carcinoma and compare them with their clinical pathological correlates.

Solid pseudopapillary neoplasms (SPN) of the pancreas are rare, low‐grade malignant neoplasms that metastasise to the liver or peritoneum in 10–15% of cases. They almost invariably present somatic activating mutations of CTNNB1. No comprehensive molecular characterisation of metastatic disease has been conducted to date. We performed whole‐exome sequencing and copy‐number variation (CNV) analysis of 10 primary SPN and comparative sequencing of five matched primary/metastatic tumour specimens by high‐coverage targeted sequencing of 409 genes. In addition to CTNNB1‐activating mutations, we found inactivating mutations of epigenetic regulators (KDM6A, TET1, BAP1) associated with metastatic disease. Most of these alterations were shared between primary and metastatic lesions, suggesting that they occurred before dissemination. Differently from mutations, the majority of CNVs were not shared among lesions from the same patients and affected genes involved in metabolic and pro‐proliferative pathways. Immunostaining of 27 SPNs showed that loss or reduction of KDM6A and BAP1 expression was significantly enriched in metastatic SPNs. Consistent with an increased transcriptional response to hypoxia in pancreatic adenocarcinomas bearing KDM6A inactivation, we showed that mutation or reduced KDM6A expression in SPNs is associated with increased expression of the HIF1α‐regulated protein GLUT1 at both primary and metastatic sites. Our results suggest that BAP1 and KDM6A function is a barrier to the development of metastasis in a subset of SPNs, which might open novel avenues for the treatment of this disease. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.