Loss of expression and prognosis value of alpha-internexin in gastroenteropancreatic neuroendocrine neoplasm

Abstract Background The neuronal intermediate filament alpha-internexin (α-internexin) is a cytoskeleton protein which is involved in the tumor initiation and progression. In this study, we examined the expression and prognosis value of α-internexin in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Methods α-internexin was detected with immunohistochemical staining in 286 tumor specimens from patients with GEP-NENs. Methylation status of α-internexin was evaluated by bisulfite genomic sequencing. We assessed the prognostic value of α-internexin and its correlation with relevant clinicalpathological characteristics. Results The reduced/loss of expression rate of α-internexin in GEP-NEN was 73.4% (210/286), while the positive expression rate was 26.6% (76/286). The difference of α-internexin deficiency was not statistically significant between gastrointestinal NENs (GI-NENs) and pancreatic NENs (pNENs). However, we found significant difference of reduced/loss of α-internexin expression among different sites of GI-NENs (χ2 = 43.470, P < 0.001). The reduced/loss of expression of α-internexin was significantly associated with poorly differentiation (P < 0.001) and advanced tumor stage (P < 0.001). Univariate analyses showed that reduced/loss of expression of α-internexin predicted worse overall survival (OS) in GEP-NEN patients (P < 0.001), especially in subtype of GI-NENs (P < 0.001). However, in multivariable regression analysis, α-internexin expression was not an independent prognostic factor. The hypermethylation of α-internexin gene was significantly correlated with protein deficiency in GI-NENs, but not in pNENs. Hypermethylation of several CpG sites was significantly associated with poorly differentiated and advanced stage (P values range from 0.018 to 0.044). However, the methylation status of α-internexin was not associated with patient OS. Conclusions The expression of α-internexin was highly heterougeneous in different sites of GEP-NENs. The reduced/loss of expression of α-internexin was closely related to tumors with aggressiveness and patient’s adverse prognosis. The hypermethylation of the regulatory region examined may be an important epigenetic regulation mechanism of α-internexin deficiency in subtype of GI-NENs

Additional file 1 of Loss of expression and prognosis value of alpha-internexin in gastroenteropancreatic neuroendocrine neoplasm

Table S1. Correlation of Îą-internexin methylation status with protein expression. (DOCX 27 kb

Table_1_Clinical implications of immune checkpoint markers and immune infiltrates in patients with thymic neuroendocrine neoplasms.docx

The potential response of immune checkpoint blockade (ICB) in thymic neuroendocrine neoplasms (T-NEN) is largely unknown and full of great expectations. The expression of immune checkpoint molecules and immune infiltrates greatly determine the response to ICB. However, studies regarding the immune landscape in T-NEN are scarce. This work was aimed to characterize the immune landscape and its association with clinical characteristics in T-NEN. The expression of programmed cell death protein 1 (PD-1) and its ligand, programmed death ligand-1 (PD-L1), and the density of tumor-infiltrating lymphocytes (TILs), monocytes, and granulocytes were determined by immunohistochemical (IHC) staining on tumor tissues from T-NEN. Immune landscapes were delineated and correlated with clinicopathological factors. We found that T-NEN with increased immune cell infiltration and enhanced expression of PD-1/PD-L1 tended to have restricted tumor size and less metastases. A higher density of CD8+ TILs was associated with a significantly lower rate of bone metastasis. In addition, we presented three cases of T-NEN who progressed after multiple lines of therapies and received ICB for alternative treatment. ICB elicited durable partial responses with satisfactory safety in two patients with atypical carcinoid, but showed resistance in 1 patient with large cell neuroendocrine carcinoma. This innovative study delineated for the first time the heterogeneous immune landscape in T-NEN and identified CD8+ TILs as a potential marker to predict bone metastasis. An “immune-inflamed” landscape with the presence of TILs predominated in T-NEN, making T-NEN a potentially favorable target for ICB treatment. Further judicious designs of “tailor-made” clinical trials of ICB in T-NEN are urgently needed.</p

Image_1_Clinical implications of immune checkpoint markers and immune infiltrates in patients with thymic neuroendocrine neoplasms.jpeg

The potential response of immune checkpoint blockade (ICB) in thymic neuroendocrine neoplasms (T-NEN) is largely unknown and full of great expectations. The expression of immune checkpoint molecules and immune infiltrates greatly determine the response to ICB. However, studies regarding the immune landscape in T-NEN are scarce. This work was aimed to characterize the immune landscape and its association with clinical characteristics in T-NEN. The expression of programmed cell death protein 1 (PD-1) and its ligand, programmed death ligand-1 (PD-L1), and the density of tumor-infiltrating lymphocytes (TILs), monocytes, and granulocytes were determined by immunohistochemical (IHC) staining on tumor tissues from T-NEN. Immune landscapes were delineated and correlated with clinicopathological factors. We found that T-NEN with increased immune cell infiltration and enhanced expression of PD-1/PD-L1 tended to have restricted tumor size and less metastases. A higher density of CD8+ TILs was associated with a significantly lower rate of bone metastasis. In addition, we presented three cases of T-NEN who progressed after multiple lines of therapies and received ICB for alternative treatment. ICB elicited durable partial responses with satisfactory safety in two patients with atypical carcinoid, but showed resistance in 1 patient with large cell neuroendocrine carcinoma. This innovative study delineated for the first time the heterogeneous immune landscape in T-NEN and identified CD8+ TILs as a potential marker to predict bone metastasis. An “immune-inflamed” landscape with the presence of TILs predominated in T-NEN, making T-NEN a potentially favorable target for ICB treatment. Further judicious designs of “tailor-made” clinical trials of ICB in T-NEN are urgently needed.</p

Clinicopathological features and prognostic validity of WHO grading classification of SI-NENs

Abstract Background The clinicopathological characteristics of small intestinal neuroendocrine neoplasms (SI-NENs) and the prognostic validity of WHO grading classification for SI-NENs are still unknown in Asian patients. Methods 277 patients and 8315 patients with SI-NENs were retrieved respectively from eleven Chinese hospitals and Surveillance, Epidemiology, and End Results (SEER) cancer registry. Overall survival was used as the major study outcome. Survival analysis using Kaplan-Meier analysis with log-rank test and cox regression analysis were applied. Results Clinicopathological characteristics of SI-NENs were quite different among different races. Duodenum was the predominant tumor site in Chinese patients and Asian/Pacific Islander patients but not in white patients from SEER database. Patients with duodenal NENs tended to have more localized disease than patients with jejunal/ileal NENs which were confirmed by patients from SEER database. Grade 3 or poorly differentiated/undifferentiated tumor were more common and tumor size was significantly larger in ampullary NENs compared with that in non-ampullary duodenal NENs. As for the prognostic validity of WHO grading classification, survival between patients with grade 1 and grade 2 disease was not significantly different. Ki-67 index of 5% might be a better threshold between grade 1 and grade 2 than Ki-67 index of 2% in SI-NENs. Conclusions Our study revealed that the clinicopathological characteristics of SI-NENs among different races were quite different. This might because duodenal NENs was much more common in Chinese patients and Asian/Pacific Islander patients. Duodenal NENs and jejunal/ileal NENs, ampullary and non-ampullary duodenal NENs shared different characteristics. Ki-67 index of 5% might be a better threshold between grade 1 and grade 2 in SI-NENs