No abstract

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) originate from neuroendocrine cells in the gastrointestinal tract. They are heterogeneous, and though initially considered rare tumors, the incidence of GEP-NENs has increased in the last few decades. Therapeutic approaches for the metastatic disease include surgery, radiological intervention by chemoembolisation, radiofrequency ablation, biological therapy in addition to somatostatin analogs, and PRRT therapy (177Lu-DOTATATE). The PI3K-AKT-mTOR pathway is essential in the regulation of protein translation, cell growth, and metabolism. Evidence suggests that the mTOR pathway is involved in malignant progression and resistance to treatment through over-activation of several mechanisms. PI3K, one of the main downstream of the Akt-mTOR axis, is mainly involved in the neoplastic process. This pathway is frequently deregulated in human tumors, making it a central target in the development of new anti-cancer treatments. Recent molecular studies identify potential targets within the PI3K/Akt/mTOR pathway in GEP-NENs. However, the use of target therapy has been known to lead to resistance due to several mechanisms such as feedback activation of alternative pathways, inactivation of protein kinases, and deregulation of the downstream mTOR components. Therefore, the specific role of targeted drugs for the management of GEP-NENs is yet to be well-defined. The variable clinical presentation of advanced neuroendocrine tumors is a significant challenge for designing studies. This review aims to highlight the role of the PI3K/Akt/mTOR pathway in the development of neuroendocrine tumors and further specify its potential as a therapeutic target in advanced stages.

Glioblastoma multiforme (GBM) and primary central nervous system lymphoma (PCNSL) are malignant cerebral neoplasms associated with poor prognosis. Early diagnosis and subsequent planning of adequate treatment strategy are relevant to improve survival and reduce neurological deficit. Two groups of patients affected by GBM and PCNSL were compared to identify: (1) factors influencing the time necessary to obtain a correct diagnosis; (2) the influence of the interval time from clinical onset to diagnosis on the prognosis. Fifty-six patients (28 PCNSL and 28 GBM, 23 females and 33 males) referred to the same hospital setting were retrospectively evaluated. The mean age at diagnosis was 61 years. The two groups were comparable in terms of age, sex, clinical symptoms at onset and performance status. There was no relevant difference in time span from clinical onset to first neuroimaging examination, while time span from first neuroimaging to final morphological diagnosis was much longer in PCNSL patients (p = 0.008). Multivariate Cox regression analysis, including both PCNSL and GBM cases, showed a significant association of the overall survival with: time to diagnosis (HR 0.06), age at onset (HR 1.04). Our results show a significant diagnostic delay in PCNSL cases. Age at onset of disease and time to diagnosis emerge as clinical factors affecting overall survival in both groups. Stereotactic-guided biopsy should be chosen as routine method to early diagnose PCNSL. The clinical relevance of early diagnosis in GBM and PCNSL needs to be emphasized to maximize the overall survival in both neoplasms.