Immunotherapy in Gastroenteropancreatic Neuroendocrine Neoplasia.

The worldwide prevalence and incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) and of NENs, in general, have been increasing recently. While valuing the considerable progress made in the treatment strategies for GEP-NEN in recent years, patients with advanced, metastasized disease still have a poor prognosis, which calls for urgent novel therapies. The immune system plays a dual role: both host-protecting and "tumor-promoting." Hence, immunotherapy is potentially a powerful weapon to help NEN patients. However, although recent successes with checkpoint inhibitors have shown that enhancing antitumor immunity can be effective, the dynamic nature of the immunosuppressive tumor microenvironment presents significant hurdles to the broader application of these therapies. Studies led to their approval in NEN of the lung and Merkel cell carcinoma, whereas results in other settings have not been so encouraging. Oncolytic viruses can selectively infect and destroy cancer cells, acting as an in situ cancer vaccine. Moreover, they can remodel the tumor microenvironment toward a T cell-inflamed phenotype. Oncolytic virotherapy has been proposed as an ablative and immunostimulatory treatment strategy for solid tumors that are resistant to checkpoint inhibitors alone. Future efforts should focus on finding the best way to include immunotherapy in the GEP-NEN treatment scenario. In this context, this study aims at providing a comprehensive generalized review of the immune checkpoint blockade and the oncolytic virotherapy use in GEP-NENs that might improve GEP-NEN treatment strategies.

Enhancing Metformin Effects by Adding Gut Microbiota Modulators to Ameliorate the Metabolic Status of Obese, Insulin-Resistant Hosts.

Obesity is a systemic disease and represents one of the leading causes of death worldwide by constituting the main risk factor for a series of non-communicable diseases such as type 2 diabetes mellitus (T2DM), cardiovascular diseases and dyslipidemia. Lifestyle interventions have been attempting to prevent T2DM and obesity but are difficult to maintain by most patients. However, the recent focus on the intestinal microbiota and its important role in the host's metabolism provides a new key for improving metabolic health. Modulating the composition of the gut microbiota was proposed as a method to manage these metabolic diseases and most frequently this is undertaken by using probiotics, prebiotics or synbiotics. Furthermore, the action of metformin, the most commonly prescribed drug for treating T2DM, is mediated in part by the gut microbiota, although this interplay may also be responsible for the frequent gastrointestinal adverse effects of metformin. Thus, adding a gut microbiota modulator (GMM), such as probiotics or prebiotics, to metformin therapy could amplify its anti-diabetic effects, while decreasing its adverse reactions. This review summarizes the various therapies that are used to shift the composition of the microbiome and their efficacy in alleviating metabolic parameters, it assesses the interaction between metformin and the gut microbiota, and it evaluates the existing clinical and preclinical studies that analyze the potential synergy of a combined metformin-GMM therapy.

Spontaneous remission of Cushing's disease: A systematic review.

Spontaneous remission is rare in Cushing's disease. We describe one illustrative case and provide a systematic review of cases previously reported in the literature. Case report: A 51-year-old woman diagnosed with Cushing's disease underwent 9 months' isolated metyrapone treatment. Two months after end of treatment, she was admitted with acute kidney failure. After another 4 months, in June 2020, there was no evidence of hypercortisolism, either clinically or biochemically, or of hypocortisolism. At the time of writing, 1 year later, she was still in remission. Cases reported in the literature: 23 patients were reported, including the present case. 87% were female with a median age of 32 years. Ten of those with radiologically visible tumors had microadenoma (44%) and 7 had macroadenoma (30%). Mean time from diagnosis to spontaneous remission was 5 months, and was shorter in macroadenoma (1 month) than in microadenoma (13.5 months). Treatments before spontaneous remission were: no treatment (65%), steroidogenesis enzyme inhibitors (22%), bilateral adrenalectomy and adrenal autotransplantation (5%), partial bilateral adrenalectomy (4%), and incomplete pituitary surgery (4%). Pituitary tumor apoplexy was the most frequently incriminated event (91%), radiologically documented in 43% of patients. Mean remission during follow-up was 28 months (range, 6-130 months). Recurrence occurred in 39% (n=9) of patients. Although several mechanisms responsible for this phenomenon have been proposed, clinical or subclinical pituitary tumor apoplexy, the latter sometimes presenting atypically, seems to be the most frequently incriminated event. Doctors should be aware of this, and regular follow-up is mandatory due to its unpredictability.

MicroRNAs and Treatment with Somatostatin Analogs in Gastro- Entero-Pancreatic Neuroendocrine Neoplasms: Challenges in Personalized Medicine.

Molecular predictive biomarkers represent an essential tool for the future of personalized oncotherapy. Gastro- entero-pancreatic neuroendocrine neoplasms are a heterogeneous group of epithelial tumors with a steady increase in incidence and prevalence. Their effective management depends on early diagnosis, personalized risk stratification, and monitoring response to therapy. A crucial element is identifying accurate biomarkers to predict/monitor therapeutic responses, assess drug resistance, and quantify residual disease in a reproducible and less invasive way. Taking into consideration their role in cell differentiation, cell proliferation, apoptosis and tumor development, microRNAs have gained interest as potential prognostic markers and treatment response predictors in neuroendocrine neoplasms. This review is the first to summarize the available data on the possible role of microRNAs in evaluating the efficacy of somatostatin analogs treatment in gastro- entero-pancreatic neuroendocrine neoplasms. Although the literature is scarce, the let-7 family targeting phosphoinositide 3 kinase - protein kinase B 1 - mammalian target of rapamycin signaling pathway might represent a promising biomarker with potential clinical benefit, but further research is required before their eventual clinical application. Furthermore, the ambiguous molecular mechanisms of neuroendocrine proliferation and the undefined signaling pathway of somatostatin analogs should encourage future research in this field that may lead to a different clinical approach to neuroendocrine disease.