Beyond Traditional Morphological Characterization of Lung Neuroendocrine Neoplasms: In Silico Study of Next-Generation Sequencing Mutations Analysis across the Four World Health Organization Defined Groups

Lung neuroendocrine neoplasms (LNENs) classes, as proposed by the World Health Organization 2015, do not provide properly prognostic and therapeutic indications. In fact, high-throughput molecular analysis, based on next-generation sequencing, identified novel molecular subgroups, associated with different genomic signatures, that could pave the way for alternative therapeutic approaches. The present review, coupled with in silico molecular analysis, could show the current genomic alterations state in actual LNENS groups. Interestingly our manuscript suggests that the molecular novelties could improve the LNENs therapeutics efficacy. In more detail, we reported the differences of gene alterations and mutational rate between LNENS, confirming the central pathogenetic role given by a different mutational rate in chromatin remodeling genes and tumor suppressors TP53-RB1. In conclusion, our results underlined that a further molecular layer is needed to improve the efficacy of LNENs medical treatment.Lung neuroendocrine neoplasms (LNENs) represent a rare and heterogeneous population of lung tumors. LNENs incidence rate has increased dramatically over the past 30 years. The current World Health Organization LNENs classification (WHO 2015), distinguished four LNENs prognostic categories, according to their morphology, necrosis amount and mitotic count: typical carcinoid (TC), atypical-carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung cancer (SCLC). At present, due to their rarity and biological heterogeneity there is still no consensus on the best therapeutic approach. Next-generation-sequencing analysis showed that WHO 2015 LNENs classes, could be characterized also by specific molecular alterations: frequently mutated genes involving chromatin remodeling and generally characterized by low mutational burden (MB) are frequently detected in both TC and AC; otherwise, TP53 and RB1 tumor suppressor genes alterations and high MB are usually detected in LCNEC and SCLC. We provide an overview concerning gene mutations in each WHO 2015 LNENs class in order to report the current LNENs mutational status as potential tool to better understand their clinical outcome and to drive medical treatment

Myeloid and T-Cell Microenvironment Immune Features Identify Two Prognostic Sub-Groups in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms

High-grade Gastroenteropancreatic Neuroendocrine neoplasms (H-NENs) comprehend well-differentiated tumors (NET G3) and poorly differentiated carcinomas (NEC) with proliferative activity indexes as mitotic count (MC) >20 mitoses/10 HPF and Ki-67 >20%. At present, no specific therapy for H-NENs exists and the several evidences of microenvironment involvement in their pathogenesis pave the way for tailored therapies. Forty-five consecutive cases, with available information about T-cell, immune, and non-immune markers, from surgical pathology and clinical databases of 2 Italian institutions were immunostained for Arginase, CD33, CD163 and CD66 myeloid markers. The association between features was assessed by Spearman's correlation coefficient. A unsupervised K-means algorithm was used to identify clusters of patients according to inputs of microenvironment features and the relationship between clusters and clinicopathological features, including cancer-specific survival (CSS), was analyzed. The H-NEN population was composed of 6 (13.3%) NET G3 and 39 (86.7%) NEC. Overall, significant positive associations were found between myeloid (CD33, CD163 and Arginase) and T/immune markers (CD3, CD4, CD8, PD-1 and HLA-I). Myeloid and T-cell markers CD3 and CD8 identified two clusters of patients from unsupervised K-means analysis. Cases grouped in cluster 1 with more myeloid infiltrates, T cell, HLA and expression of inhibitory receptors and ligands in the stroma (PD-1, PD-L1) had significantly better CSS than patients in cluster 2. Multivariable analysis showed that Ki-67 (>55 vs. <55, HR 8.60, CI 95% 2.61-28.33, p < 0.0001) and cluster (1 vs. 2, HR 0.43, CI 95% 0.20-0.93, p = 0.03) were significantly associated with survival. High grade gastroenteropancreatic neuroendocrine neoplasms can be further classified into two prognostic sub-populations of tumors driven by different tumor microenvironments and immune features able to generate the framework for evaluating new therapeutic strategies

Ascl1 and OTP tumor expressions are associated with Disease-Free Survival in Lung Atypical Carcinoids

Background: According to World Health Organization guidelines, Atypical Carcinoids (ACs) are well-differentiated lung neuroendocrine tumors with 2-10 mitoses/2 mm2 and/or foci of necrosis (usually punctate). Besides morphological criteria no further tools in predicting AC clinical outcome are proposed. Aim of this work was to identify novel factors able to predict AC disease aggressiveness and progression. Methods and results: Three hundred-seventy lung carcinoids were collected and centrally reviewed by two expert pathologists. Morphology and immunohistochemical markers (Ki-67, TTF-1, CD44, OTP, SSTR2A, Ascl1, p53 and Rb1) were studied and correlated with disease free survival (DFS) and overall survival (OS). Fifty-eight of 370 tumors were defined as AC. Survival analysis showed that patients with Ascl1+ACs and those with OTP-ACs had a significantly worse DFS than patients with Ascl1-ACs and OTP+ACs, respectively. Combining Ascl1 and OTP expressions, groups were formed reflecting the aggressiveness of disease (p=0.0005). Ki-67 ≥10% patients had a significantly worse DFS than patients with Ki-67<10%. At multivariable analysis Ascl1 (present vs absent, HR=3.42, 95%CI 1.35-8.65, p=0.009) and OTP (present vs absent, HR=0.26, 95%CI 0.10-0.68, p=0.006) were independently associated with DFS. The prognosis of patients with Ki-67 ≥10% tended to be worse compared to that with Ki-67<10%. On the contrary, OTP (present vs absent, HR=0.28, 95%CI 0.09-0.89, p=0.03), tumor stage (III-IV vs I-II, HR=4.25, 95%CI 1.42-12.73, p=0.01) and increasing age (10-year increase, HR=1.67, 95%CI 1.04-2.68, p=0.03) were independently associated with OS. Conclusions: This retrospective analysis of lung ACs showed that Ascl1 and OTP could be the main prognostic drivers of post-operative recurrence

Lung Carcinoid Tumors: Histology and Ki-67, The Eternal Rivalry

WHO classification of Thoracic Tumors defines lung carcinoid tumors (LCTs) as well-differentiated neuroendocrine neoplasms (NENs) classified in low grade typical (TC) and intermediate grade atypical carcinoids (AC). Limited data exist concerning protein expression and morphologic factors able to predict disease aggressiveness. Though Ki-67 has proved to be a powerful diagnostic and prognostic factor for Gastro-entero-pancreatic NENs, its role in lung NENs is still debated

Lung Carcinoid Tumors: Histology and Ki-67, The Eternal Rivalry

WHO classification of Thoracic Tumors defines lung carcinoid tumors (LCTs) as well-differentiated neuroendocrine neoplasms (NENs) classified in low grade typical (TC) and intermediate grade atypical carcinoids (AC). Limited data exist concerning protein expression and morphologic factors able to predict disease aggressiveness. Though Ki-67 has proved to be a powerful diagnostic and prognostic factor for Gastro-entero-pancreatic NENs, its role in lung NENs is still debated