Expression Of Signal Biomarkers In Pancreatic Neuroendocrine Neoplasms And Their Clinical Implications

Part1Clinicopathological characteristics and prognosis-related factors of resectable pancreatic neuroendocrine neoplasms:a retrospective study of112cases in a single centerObjective The aim of this preliminary study was to describe the clinicopathological characteristics of pancreatic neuroendocrine neoplasms (pNENs) and to evaluate prognostic factors for prediction of postoperative outcomes in pancreatic neuroendocrine neoplasms.Methods Clinical data of112patients with pNENs underwent surgery at the ZhongShan Hospital of Fudan University between January1999and December2011were analyzed retrospectively.Results A total of112patients (mean age52.0±14.6years, females48.2%, males51.8%) with pNENs,104patients (92.9%) were neuroendocrine tumor.5patients (4.5%) were neuroendocrine carcinoma and3patients (2.7%) were mixed adenoendocrine carcinoma. The percentage of G1, G2and G3tumors were52.7%,40.2%and7.1%respectively. The percentage of TNM stage Ⅰ, stage Ⅱ, stage Ⅲ and stage IV tumors were23.2%,43.8%,24.1%and8.9%respectively. The median tumor size was3.5cm (range0.8-18.0). In9cases (8.0%), the tumor was multifocal. Concurrently, four pNENs patients had Multiple Endocrine Neoplasia type1(MEN-1) syndrome and two patients had von Hippel-Lindau disease in association with familial syndromes. At diagnosis, tumors were localized in69.6%of the patients, regional spread including lympa nodes metastases or/and extrapancreatic organ invasions occurred in30.4%of the patients and distant metastases occurred in8.9%of the patients. Considering the19cases with liver metastases,10cases were synchronous liver metastases and9cases were metachronous liver metastases.27patients (24.1%) had nerve invasion and37patients (33.0%) had tumor necrosis.27pNENs (24.1%) were functioning tumors whereas85pNENs (75.9%) were non-functioning tumors. NF-pNENs were significantly more represented among patients with large tumors, advanced age, liver metastases and advanced grading. Immunohistochemistry staining positive rates of CgA, Syn were90.4%(85/94),48.4%(45/93) and87.2%(34/39), respectively. The SSTR2A positive rates of functioning and non-functioning pNENs were79.2%(19/24) and77.6%(52/67).109patients (97.3%) underwent radical resection. The overall1-,2-,5-, and10-year accumulative survival rates were95%,93%,91%and81%, respectively. The median survival time was144.0months. Survival rate in older patients (>60years) and patients with high ki-67index (Ki-67>2%), regional lymph nodes metastasis, liver metastases, nerve invasion and major vascular invasion were significantly lower than those younger patients (≤60years), patients with low ki-67index (Ki-67<2%), patients without regional lymph nodes metastasis, liver metastases, nerve invasion and major vascular invasion. However, elderly patients, major vascular invasion and high ki-67index were independent predictors for survival.Conclusion pNENs are a broad family of tumors with a wide range of clinical presentations and outcomes. A host of factors affected survival durations in pNENs. Elderly patients, major vascular invasion and high ki-67index were independent predictors. Patients who underwent radical operation appeared to achieve an acceptable long-term prognostic benefit.Part2Expression of signal biomarkers in pancreatic neuroendocrine neoplasms and their clinical implicationsObjective:The purpose of this study was to clarify the expression patterns of EGFR, p-mTOR, mTOR, PTEN, CK19and KIT in primary pancreatic neuroendocrine neoplasms (pNENs) and their significance in predicting clinical behaviors and postoperative outcomes.Methods:The expressions of EGFR, p-mTOR, mTOR, PTEN, CK19and KIT were assessed in normal pancreatic islets and in resectable pNENs using immunohistochemistry. Associations of immunohistochemical features with clinicopathologic characteristics and prognosis were evaluated. Results:Strongly positive staining was observed for both mTOR and PTEN in normal pancreatic islets, whereas negative staining was observed for EGFR and p-mTOR. All samples were negative for both KIT and CK19in normal pancreatic islets. In primary pNENs, EGFR and p-mTOR positive rates were60.0%(54/90) and44.4%(40/90), mTOR positive rate of was70.8%(63/89), and high expression rate of PTEN was56.7%(51/90) whereas low expression rate was43.4%(39/90). Positive rates for KIT and CK19in pNENs were49.5%(45/91) and71.4%(65/91), and high expression rate were17.6%(16/91) and57.1%(52/91), respectively. In terms of EGFR/mTOR/PTEN pathway, the EGFR expressions strongly correlate with p-mTOR expressions (P<0.05). EGFR positive was correlated with regional lymph nodes metastases, advanced TNM stage and higher ki-67index (P<0.05). No significant correlation between p-mTOR positive and clinicopathological characteristics was found. PTEN loss (low expression) was more frequent in advanced WHO grades and higher ki-67index (P<0.05). Survival rate in patients with positive EGFR were significantly worse than negative EGFR (P<0.05).Patients with high expression of PTEN or negative p-mTOR had increased5-year survival rates which showed a tendency to prolong survival duration compared with the patients with their counterparts. Multivariate analysis verified that positive EGFR were independent predictors for survival (P<0.05). As for KIT and CK19, Ki-67index was higher in KIT positive subgroup than in KIT negative subgroup (P<0.05), however, no statistically significant difference of Ki-67index was found between CK19positive and negative subgroups (P>0.05). The positive CK19expression was significantly associated with non-functioning tumors, regional lymph nodes metastases and advanced TNM stage (P<0.05), Meanwhile, the positive KIT expression was significantly associated with advanced TNM stage (P<0.05), but other features approached statistical significance. In survival analysis, overall survival in patients with CK19positive or KIT positive had lower5-year survival rates which showed a tendency to reduce survival duration compared with their counterparts (P>0.05) and the hazard ratio of CK19positive and KIT positive pNENs were5.07and2.57. In our CK19/KIT immunohistochemical classification system, patients in "intermediate/high risk" subgroup showed obvious poorer prognosis than those in "low risk" subgroup from survival curve (P=0.130) and5-year OS was differential and the hazard ratio was29.5. There was a significant difference in functioning status among the3risk levels (P<0.05).It seemed that patients with high risk were more prone to had regional lymph nodes metastases, distant metastases and/or recurrences which approached statistical significance from pairwise comparisons.Conclusion:Our study suggested that p-mTOR positive, EGFR positive and PTEN loss might have synergic effect on tumorigenesis and proliferation which were related to poor prognosis. Collectively, further investigation should be conducted in the targeted therapy based on EGFR/mTOR/PTEN signal pathway and associated molecular mechanism in pancreatic neuroendocrine neoplasms. Meanwhile, we indicated that CK19and KIT expression was associated with aggressive clinical behavior in pNENs. Elevated CK19and KIT might have an effect on tumor development and metastases which was related to poor prognosis and malignant behavior. The immunohistochemical classification system may be regarded as useful criteria predicting postoperative outcomes. Finally, further evaluation in larger-scale clinical validation studies should be conducted in the targeted therapy based on KIT signaling pathway and CK19associated molecular mechanism in pNENs.