Changes of soil nutrients and organic carbon fractions in Caragana korshinskii forests with different restoration years in mountainous areas of southern Ningxia, China.

Vegetation restoration can effectively enhance soil quality and soil organic carbon (SOC) sequestration. In this study, the distribution characteristics of soil nutrients and SOC along soil profile (0-100 cm), and their responses to restoration years (16, 28, 38 years) were studied in Caragana korshinskii plantations in the southern mountainous area of Ningxia, compared with cropland and natural grassland. The results showed that: 1) the contents of SOC, soil total nitrogen (TN), total phosphorus (TP), particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and the proportion of particulate organic carbon to total organic carbon (POC/SOC) all decreased with increasing soil depth. The ratio of mineral-associated organic carbon to total organic carbon (MAOC/SOC) exhibited an opposite trend. 2) The contents of SOC, TN, TP, C:P, N:P, POC and MAOC gra-dually decreased as the restoration years increased. However, the C:N ratio showed no significant change. The POC/SOC ratio initially increased and then decreased, while the MAOC/SOC ratio decreased initially and then increased. 3) In three different types of vegetation, POC, MAOC, and SOC showed a highly significant positive linear correlation, with the increase in SOC mainly depended on the increase in MAOC. The SOC, TN, TP, POC and MAOC contents in natural grassland and C. korshinskii plantations were significantly higher than those in cropland. In conclusion, soil nutrients and POC and MAOC contents of C. korshinskii plantations gradually decreased with the increases in restoration years. However, when compared with cropland, natural grassland and C. korshinskii plantations demonstrated a greater capacity to maintain and enhance soil nutrient and carbon storage.

SQSTM1/p62 is a prognostic molecular marker and potential therapeutic target for pancreatic neuroendocrine tumours.

BACKGROUND: There have been few studies on the role of autophagy in pancreatic neuroendocrine tumours (PNETs). SQSTM1/p62 (also called Sequestosome 1) is a potential autophagy regulator, and its biological roles and clinical significance in PNETs remain poorly understood. PURPOSE: The purpose of this study was to evaluate the clinical significance of SQSTM1/p62 in human PNET specimens and to evaluate its potential value as a therapeutic target by studying its biological function in PNET cell lines. METHODS: SQSTM1/p62 protein expression was assessed in 106 PNET patient specimens by immunohistochemistry, and the relationship between SQSTM1/p62 protein expression and the clinicopathological features of PNETs in patients was analysed. The proliferation, invasion and apoptosis of SQSTM1/p62-knockdown QGP-1 and INS-1 cells were assessed by the MTT assay, a Transwell assay and flow cytometry. Cell autophagy was assessed by western blotting and mCherry-GFP-LC3B. RESULTS: The protein expression of SQSTM1/p62 in PNET patient specimens was significantly correlated with tumour recurrence (p = 0.005) and worse prognosis (log rank p = 0.020). Downregulation of the SQSTM1/p62 gene inhibited tumour cell proliferation and migration and induced PNET cell death. Downregulation of SQSTM1/p62 activated autophagy in PNET cell lines but blocked autophagic flow. Knockdown of the SQSTM1/p62 gene inhibited mTOR phosphorylation. CONCLUSION: The SQSTM1/P62 protein could be an independent prognostic marker for PNET patients. Downregulating SQSTM1/P62 can inhibit PNET progression, inhibit mTOR phosphorylation and block autophagic flow.

Dickkopf-related protein 1/cytoskeleton-associated protein 4 signaling activation by Helicobacter pylori-induced activator protein-1 promotes gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

BACKGROUND: Gastric cancer (GC) is a common malignant tumor with high incidence and mortality rates globally, especially in East Asian countries. Helicobacter pylori (H. pylori) infection is a significant and independent risk factor for GC. However, its underlying mechanism of action is not fully understood. Dickkopf-related protein (DKK) 1 is a Wnt signaling antagonist, and cytoskeleton-associated protein (CKAP) 4 is a newly identified DKK1 receptor. Recent studies found that the binding of DKK1 to CAKP4 mediated the procancer signaling of DKK1 inde-pendent of Wnt signaling. We hypothesize that H. pylori-induced activation of DKK1/CKAP4 signaling contributes to the initiation and progression of GC. AIM: To investigate the interaction of H. pylori infection, DKK1 and CAKP4 in GC, as well as the underlying molecular mechanisms. METHODS: RNA sequencing was used to identify differentially expressed genes (DEGs) between H. pylori-infected and uninfected primary GC cells. Gain- and loss-of-function experiments were performed to verify the H. pylori-induced upregulation of activator protein-1 (AP-1) in GC cells. A dual-luciferase reporter assay and co-immunoprecipitation were used to determine the binding of AP-1 to the DKK1 promoter and DKK1 to CKAP4. Western blotting and immunohistochemistry detected the expression of DKK1, CKAP4, and phos-phatidylinositol 3-kinase (PI3K) pathway-related proteins in GC cells and tissues. Functional experiments and tumorigenicity in nude mice detected malignant behavior of GC cells in vitro and in vivo. RESULTS: We identified 32 DEGs between primary GC cells with and without H. pylori infection, including JUN, fos-like antigen-1 (FOSL1), and DKK1, and confirmed that the three proteins and CKAP4 were highly expressed in H. pylori-infected GC cells, H. pylori-infected gerbil gastric tissues, and human GC tissues. JUN and FOSL1 form AP-1 to transcriptionally activate DKK1 expression by binding to the DKK1 promoter. Activated DKK1 bound to CKAP4, but not the most common Wnt coreceptor low-density lipoprotein receptor-related protein 5/6, to promote GC cell growth, colony formation, migration, invasion, and xenograft tumor growth in nude mice. All these effects were driven by activation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway. Targeting the PI3K signaling pathway by LY294002 inhibited DKK1-mediated CKAP4/PI3K signaling activity and the malignant behavior of GC cells. CONCLUSION: H. pylori induces JUN and FOSL1 expression to form AP-1, which transcriptionally activates DKK1. Binding of DKK1 to KAKP4 contributes to gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

Mutation and Expression of Gene YY1 in Pancreatic Neuroendocrine Tumors and Its Clinical Significance.

OBJECTIVE: The clinical significance of the YY1 gene mutation and expression in pancreatic neuroendocrine tumors (PNETs) remains unknown. Therefore, this study aimed to comprehensively analyze the somatic mutation of YY1 in the different subtypes of PNETs. METHODS: A total of 143 PNETs were assessed by Sanger sequencing to identify the somatic mutation of YY1 gene in various subtypes of PNETs. YY1 protein expression was examined in 103 PNETs by immunohistochemical staining and western blot. Gene mutation and its protein expression were correlated with clinicopathologic features. RESULTS: A recurrent mutation (chr14:100743807C>G) in the YY1 gene was identified in 15 of 83 insulinomas (18%) and in only 1 of 60 noninsulinoma PNETs (1.7%) (P = .0045). The YY1 mutation was not found in MEN1-associated insulinomas. The YY1 mutation in insulinomas was correlated with older age and lower serum glucose levels (age, 57 vs 42.5 years, P = .006; blood glucose, 25.2 vs 33.6 mg/dL, P = .008). YY1 protein expression was found in 100 of 103 PNETs, although expression was weaker in metastases than in localized tumors (P = .036). The stronger expression of YY1 protein was associated with favorable disease-free survival of patients with PNETs (log-rank, P = .011; n = 70). Multivariable statistical analysis showed that YY1 protein expression could be an independent predictor of prognosis. CONCLUSION: The hotspot YY1 mutation mostly occurred in insulinomas and rarely in noninsulinoma PNETs. The stronger YY1 protein expression was correlated with the better prognosis of PNETs patients.

Plasma levels of acylated ghrelin in patients with insulinoma and expression of ghrelin and its receptor in insulinomas.

BACKGROUND: Insulinoma is a subtype of pancreatic neuroendocrine tumors. Many patients with insulinoma are obese due to frequent food intake. Ghrelin is associated with obesity and blood levels of insulin. It is not clear if plasma levels of ghrelin in insulinoma patients correlate with hyperinsulinemia and obesity. Expression of ghrelin and its receptor has not been well demonstrated in insulinoma. OBJECTIVE: To study if plasma levels of ghrelin is associated with obesity and hyperinsulinemia or hyperproinsulinemia in patients with insulinoma, and to detect the expression of ghrelin and its receptor in insulinoma. METHODS: Plasma levels of acylated ghrelin, insulin, and proinsulin were measured in 37 patients with insulinoma and 25 controls by ELISA. Expression of ghrelin and its receptor GHS-R1A was examined in 20 insulinoma and paired pancreatic specimens by immunostaining. P ≤ 0.05 was considered significant. RESULTS: The plasma levels of acylated ghrelin in patients with insulinoma were significantly lower than that in the controls (median 15 pg/ml vs. 19 pg/ml, respectively, P = 0.016). The reduced plasma levels of acylated ghrelin in patients were significantly correlated with obesity, hyperinsulinemia, and hyperproinsulinemia (P = 0.029 and P = 0.028, respectively). Expression of ghrelin and its receptor GHS-R1A was shown in the majority of insulinoma specimens. The expression of GHS-R1A was positively correlated with ghrelin expression in insulinoma (P = 0.014). CONCLUSIONS: Plasma levels of acylated ghrelin decreased in patients with insulinoma, probably due to the hyperinsulinemia and obesity in the patients. Expression of both ghrelin and its receptor is common in insulinoma.

Pseudo-hemorrhagic region formation in pancreatic neuroendocrine tumors is a result of blood vessel dilation followed by endothelial cell detachment.

Aberrant blood vessel formation and hemorrhage may contribute to tumor progression and are potential targets in the treatment of several types of cancer. Pancreatic neuroendocrine tumors (PNETs) are highly vascularized, particularly when they are well-differentiated. However, the process of vascularization and endothelial cell detachment in PNETs is poorly understood. In the present study, 132 PNET clinical samples were examined and a special type of hemorrhagic region was observed in ~30% of the samples regardless of tumor subtype. These hemorrhagic regions were presented as blood-filled caverns with a smooth boundary and were unlined by endothelial cells. Based on the extensive endothelial cell detachment observed in the clinical samples, the formation process of these blood-filled caverns was hypothesized. Blood vessel dilation followed by detachment of endothelial cells from the surrounding tumor tissue was speculated. This was further supported using an INS-1 xenograft insulinoma model. As the formation process was distinct from the typical diffusive hemorrhage, it was named 'pseudo-hemorrhage'. Furthermore, it was demonstrated that epithelial (E-) cadherin and ß-catenin were overexpressed in tumor cells surrounding these pseudo-hemorrhagic regions. Therefore, even though no statistically significant association of pseudo-hemorrhage with clinical features (metastasis or disease recurrence) was identified, the high levels of E-cadherin and ß-catenin expression may suggest that a number of features of normal islet cells are retained.

A nation-wide retrospective epidemiological study of gastroenteropancreatic neuroendocrine neoplasms in china.

BACKGROUND: Representative data on the gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) in Asian patients is rare, especially in China. This study aims to create a GEP-NENs profile of Chinese patients. METHODS: This was a hospital-based, nation-wide, and multi-center 10-year (2001-2010) retrospective study which collected GEP-NEN patients' information in tertiary referral hospitals. All 2010 inpatient GEP-NEN cases with confirmed pathology in the selected hospitals were included. The primary GEP-NEN sites were measured and the epidemiological and clinical information of each tumor site were compared. RESULTS: The most common primary sites for GEP-NEN were the pancreas (31.5%) and rectum (29.6%), followed by the cardia (11.6%) and body (15.4%) of stomach. Small intestinal and colonic NENs took up a relatively small proportion of all patients. Pancreatic and rectal NENs, rather than cardiac and gastric body NENs, tended to be found in younger (P<0.001), female (P<0.001), urban (P<0.001) residents with a higher education level (P=0.032) and were also diagnosed at earlier stage (P<0.001) and lower grade (P<0.001). Surgery remained the primary treatment method in all groups. CONCLUSIONS: More studies on the commonality and heterogeneity of GEP-NENs are warranted to improve diagnosis efficiencies and treatment outcomes.

Prognostic relevance of UCH-L1 and α-internexin in pancreatic neuroendocrine tumors.

Prognostic biomarkers for the pancreatic neuroendocrine tumors are needed. Proteomic study on insulinoma has been rarely reported. We identified the differential expression of proteins between insulinoma and their paired tissues by proteomic analysis, and evaluated the prognostic significance of specific proteins in pancreatic neuroendocrine tumors including insulinoma. The differential expression of select proteins was validated in more than 300 tumors using immunohistochemical staining and western blot. Methylation of UCH-L1 promoter in tumors was examined by methylation specific PCR and validated by sequencing. The concurrent expression of UCH-L1 and α-internexin was correlated with the prognosis in 2 independent collectives of patients with tumors. Sixty-two and 219 proteins were significantly down-regulated and up-regulated in insulinomas, respectively. Demethylation of UCH-L1 promoter was associated with UCH-L1 expression in tumors (p = 0.002). The concurrent expression of UCH-L1 and α-internexin in pancreatic neuroendocrine tumors was significantly associated with better overall survival and disease-free survival in the combination of both cohorts (log rank p = 3.90 × 10-4 and p = 3.75 × 10-5, respectively) and in each of cohorts. The prognostic value of both proteins was also validated in patients with stage II and III tumors (p = 0.017 and p = 0.006, respectively). The proteins UCH-L1 and α-internexin could be independent prognostic biomarkers of pancreatic neuroendocrine tumors.

High expression of PTBP1 promote invasion of colorectal cancer by alternative splicing of cortactin.

Polypyrimidine tract-binding protein 1 (PTBP1) involving in almost all steps of mRNA regulation including alternative splicing metabolism during tumorigenesis due to its RNA-binding activity. Initially, we found that high expressed PTBP1 and poor prognosis was interrelated in colorectal cancer (CRC) patients with stages II and III CRC, which widely different in prognosis and treatment, by immunohistochemistry. PTBP1 was also upregulated in colon cancer cell lines. In our study, knockdown of PTBP1 by siRNA transfection decreased cell proliferation and invasion in vitro. Denovirus shRNA knockdown of PTBP1 inhibited colorectal cancer growth in vivo. Furthermore, PTBP1 regulates alternative splicing of many target genes involving in tumorgenesis in colon cancer cells. We confirmed that the splicing of cortactin exon 11 which was only contained in cortactin isoform-a, as a PTBP1 target. Knockdown of PTBP1 decreased the expression of cortactin isoform-a by exclusion of exon 11. Also the mRNA levels of PTBP1 and cortactin isoform-a were cooperatively expressed in colorectal cancer tissues. Knocking down cortactin isoform-a significantly decreased cell migration and invasion in colorectal cancer cells. Overexpression of cortactin isoform-a could rescue PTBP1-knockdown effect of cell motility. In summary the study revealed that PTBP1 facilitates colorectal cancer migration and invasion activities by inclusion of cortactin exon 11.

A Clinicopathological Study of Malignant Insulinoma in a Contemporary Series.

OBJECTIVE: The aim of the study was to address the origin and natural history of malignant insulinoma. METHODS: Retrospective review of medical records of patients diagnosed with insulinoma at Cedars-Sinai Medical Center between 2000 and 2015 was conducted. Hormonal expression in tumor specimens was examined by immunostaining. RESULTS: All the 9 patients with malignant insulinoma (35% of 26 patients with insulinoma) already had liver metastasis at hypoglycemia presentation with bulky cumulative tumor burden. Six patients had de novo diagnosis, 2 had known metastatic nonfunctioning pancreatic neuroendocrine tumor, and 1 had a known pancreatic mass. Tumor grade at presentation was G1 in 4 patients, G2 in 4, and unknown in 1. Four patients died 2 to 32 months after presentation, all with extensive liver tumor involvement. Tumor expression of proinsulin and insulin was heterogeneous and overall infrequent. The proinsulin levels and proinsulin/insulin molar ratio in patients with malignant versus benign insulinoma were 334 versus 44 pmol/L and 2.1 versus 0.9, respectively. CONCLUSIONS: Malignant insulinoma seems to arise from and behave like nonfunctioning pancreatic neuroendocrine tumor oncologically but with metachronous hyperinsulinemic hypoglycemia. High proinsulin levels and proinsulin/insulin molar ratio may suggest malignant insulinoma.

Differences and Similarities in the Clinicopathological Features of Pancreatic Neuroendocrine Tumors in China and the United States: A Multicenter Study.

The presentation, pathology, and prognosis of pancreatic neuroendocrine tumors (PNETs) in Asian patients have not been studied in large cohorts. We hypothesized that the clinicopathological features of PNETs of Chinese patients might be different from those of US patients. The objectives of this study were to address whether PNETs in Chinese patients exhibit unique clinicopathological features and natural history, and can be graded and staged using the WHO/ENETS criteria. This is a retrospective review of medical records of patients with PNETs in multiple academic medical centers in China (7) and the United States (2). Tumor grading and staging were based on WHO/ENETS criteria. The clinicopathological features of PNETs of Chinese and US patients were compared. Univariate and multivariate analyses were performed to find associations between survival and patient demographics, tumor grade and stage, and other clinicopathological characteristics. A total of 977 (527 Chinese and 450 US) patients with PNETs were studied. In general, Chinese patients were younger than US patients (median age 46 vs 56 years). In Chinese patients, insulinomas were the most common (52.2%), followed by nonfunctional tumors (39.7%), whereas the order was reversed in US patients. Tumor grade distribution was similar in the 2 countries (G1: 57.5% vs 55.0%; G2: 38.5% vs 41.3%; and G3: 4.0% vs 3.7%). However, age, primary tumor size, primary tumor location, grade, and stage of subtypes of PNETs were significantly different between the 2 countries. The Chinese nonfunctional tumors were significantly larger than US ones (median size 4 vs 3 cm) and more frequently located in the head/neck region (54.9% vs 34.8%). The Chinese and US insulinomas were similar in size (median 1.5 cm) but the Chinese insulinomas relatively more frequently located in the head/neck region (48.3% vs 26.1%). Higher grade, advanced stage, metastasis, and larger primary tumor size were significantly associated with unfavorable survival in both countries. Several clinicopathological differences are found between Chinese and US PNETs but the PNETs of both countries follow a similar natural history. The WHO tumor grading and ENETS staging criteria are applicable to both Chinese and US patients.

Islet Cells Serve as Cells of Origin of Pancreatic Gastrin-Positive Endocrine Tumors.

The cells of origin of pancreatic gastrinomas remain an enigma, since no gastrin-expressing cells are found in the normal adult pancreas. It was proposed that the cellular origin of pancreatic gastrinomas may come from either the pancreatic cells themselves or gastrin-expressing cells which have migrated from the duodenum. In the current study, we further characterized previously described transient pancreatic gastrin-expressing cells using cell lineage tracing in a pan-pancreatic progenitor and a pancreatic endocrine progenitor model. We provide evidence showing that pancreatic gastrin-expressing cells, found from embryonic day 12.5 until postnatal day 7, are derived from pancreatic Ptf1a(+) and neurogenin 3-expressing (Ngn3(+)) progenitors. Importantly, the majority of them coexpress glucagon, with 4% coexpressing insulin, indicating that they are a temporary subpopulation of both alpha and beta cells. Interestingly, Men1 disruption in both Ngn3 progenitors and beta and alpha cells resulted in the development of pancreatic gastrin-expressing tumors, suggesting that the latter developed from islet cells. Finally, we detected gastrin expression using three human cohorts with pancreatic endocrine tumors (pNETs) that have not been diagnosed as gastrinomas (in 9/34 pNETs from 6/14 patients with multiple endocrine neoplasia type 1, in 5/35 sporadic nonfunctioning pNETs, and in 2/20 sporadic insulinomas), consistent with observations made in mouse models. Our work provides insight into the histogenesis of pancreatic gastrin-expressing tumors.

Chromogranin A is a reliable serum diagnostic biomarker for pancreatic neuroendocrine tumors but not for insulinomas.

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) are a group of rare tumors. Chromogranin A (CgA) was considered as the most practical and useful serum tumor marker in PNET patients. But peripheral blood levels of CgA are not routinely tested in Chinese patients with PNETs. This study was to assess the diagnostic value of CgA in Chinese patients with PNETs especially in patients with insulinomas. METHODS: Eighty-nine patients with PNETs including 57 insulinomas and 32 non-insulinoma PNETs as well as 86 healthy participants were enrolled in this study between September 2003 and June 2013. Serum levels of CgA were measured by ELISA method. Expression of CgA protein was detected in 26 PNET tissues including 14 insulinomas by immunohistochemical staining. RESULTS: Serum levels of CgA in 89 PNET patients were significantly higher than that in healthy controls (P = 7.2 × 10-9). Serum levels of CgA in 57 patients with insulinomas (median 64.8 ng/ml, range 25-164) were slightly higher than the levels in healthy controls (median 53.4 ng/ml, range 39-94) but much lower than the levels in 32 patients with non-insulinoma PNETs (median 193 ng/ml, range 27-9021), P = 0.001. The serum CgA levels were reduced in 16 of 17 patients with insulinomas after tumor resection. ROC curve showed that CgA values at 60 ng/ml distinguished patients with insulinomas from healthy controls but its sensitivity and specificity were 66.7% and 73.3%, respectively. In contrast, CgA values at 74 ng/ml distinguished patients with non-insulinoma PNETs from healthy controls, and the sensitivity and specificity were 65.6% and 91.9%, respectively. Except for two insulinomas with negative staining of CgA, 12 insulinoma tissues showed positive staining of CgA. CONCLUSION: CgA is a reliable serum diagnostic biomarker for PNETs but not for insulinomas.

Expression of O(6)-methylguanine DNA methyltransferase (MGMT) and its clinical significance in gastroenteropancreatic neuroendocrine neoplasm.

O(6)-methylguanine-DNA methyltransferase (MGMT) is a widespread DNA repair enzyme defending against mutation caused by guanine O(6)-alkylating agents. Until now, we know only little about the expression of MGMT in gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN). To study the expression of MGMT and its clinical significance in GEP-NEN, 174 specimens of GEP-NEN were examined, of which 152 specimens came from The First Affiliated Hospital, Sun Yat-sen University during October 1995 to November 2013, 22 specimens came from Peking Union Medical College Hospital during September 2004 to April 2010. MGMT protein was detected with EnVision immunohistochemical staining method. Clinicopathological factors were also collected and analyzed. We observed that the overall expression rate of MGMT was 83.9%. Over expression of MGMT protein was not associated with sex, age, functional status, primary tumor location, grading, classification, TNM stage and metastasis (P > 0.05). Kaplan-Meier analysis revealed that there was no significant difference in survival between MGMT-positive and MGMT-negative tumors of GEP-NEN patients (χ(2) = 0.887, P = 0.346). In multivariate analyses carried out by Cox proportional hazards regression model, MGMT expression was also not an independent predictors of survival. These results demonstrated that MGMT protein was highly expressed in GEP-NEN. MGMT deficiency rate was similar in pancreatic NEN and in gastrointestinal NEN. MGMT expression was not correlated with prognosis of GEP-NEN.

α-Internexin: a novel biomarker for pancreatic neuroendocrine tumor aggressiveness.

PURPOSE: We aimed to test whether α-internexin could be a molecular biomarker of tumor aggressiveness and prognosis in pancreatic neuroendocrine tumors (PNETs). PATIENTS AND METHODS: Using immunohistochemical staining and Western blot, we detected the expression of α-internexin in 350 tumors from 343 patients, of whom 257 were followed up. Methylation of α-internexin promoter was examined by bisulfite sequencing to identify the crucial region that determines gene expression. Methylation of gene promoter in tumors was quantitatively measured by denaturing high performance liquid chromatography (DHPLC). We correlated α-internexin expression with clinicopathological characteristics. RESULTS: α-Internexin was expressed in 53% of 350 PNETs. The reduced expression of α-internexin was significantly associated with advanced stage (P < .0001), metastases (P < .0001), and recurrence (P = .003). α-Internexin expression was found in 57.1% of 212 surviving patients and in 17.1% of 35 deceased patients (P < .0001). Reduced expression of α-internexin was associated with shorter overall survival in PNET patients (log rank P < .0001) as well as in patients with noninsulinoma and nonfunctional (NF)-PNETs (log rank P = 0.0073 and P = 0.010, respectively). The crucial region of α-internexin promoter (-149 to +96 nucleotides [nt]) was identified, and the hypomethylation of this area in PNETs was significantly associated with gene expression (P = .015). CONCLUSION: α-Internexin can be a useful prognostic biomarker for PNETs.

S100P, a potential novel prognostic marker in colorectal cancer.

Previous studies have shown that S100P contributes to the development of a number of tumors. However, its prognostic significance in colorectal cancer (CRC) has not been demonstrated. This study aimed to confirm the expression of S100P in colorectal cancer as well as the epigenetic mechanism underlying its gene expression, and to demonstrate whether S100P could be used to predict prognosis as a biomarker. We tested the expression of S100P in 96 CRCs and their paired tissue controls, as well as 13 colon cancer cell lines by RT-PCR and western blotting. Expression of the S100P protein and mRNA was significantly higher in cancerous regions compared to that in paired non-cancerous tissues (P=4.59 x 10(-17), 0.005 respectively). The expression was significantly correlated with the hypomethylation of the S100P promoter (P=4.92 x 10(-5)), which was detected by bisulphite sequencing PCR (BSP) and quantitative methylation-specific real-time PCR (QMSP). In stages I to III, the patients with positive expression of S100P protein showed poorer overall survival compared to those with S100P negative expression, P=0.031. We also measured the preoperative serum S100P levels by ELISA. The patients with normal serum levels of S100P showed favorable prognosis compared with patients with elevated S100P levels (P=0.008). These data suggest that S100P protein may be a potential novel prognostic biomarker in CRC patients.

Clinical implications of microsatellite instability and MLH1 gene inactivation in sporadic insulinomas.

CONTEXT: The molecular pathogenesis of sporadic insulinomas is unknown. There is a lack of biomarker to distinguish benign and malignant form of insulinoma. OBJECTIVE: Our objective was to confirm the occurrence of microsatellite instability (MSI) in insulinomas, to identify alterations of mismatch repair (MMR) genes in the tumors, and to evaluate the possibility to distinguish benign and malignant insulinoma or to predict the clinical outcome of patients with these alterations. DESIGN AND PATIENTS: We detected MSI and inactivation of MLH1 gene in 55 sporadic insulinomas by PCR, immunohistochemical staining, allelic typing, analysis of promoter methylation, and exon mutations. Their correlations with clinicopathological characteristics were analyzed with univariate and multivariate statistic analysis. RESULTS: A high rate of MSI (MSI-H) was found in 33% of sporadic insulinomas. Reduced expression of mutL homolog 1 (MLH1) protein was observed in 36% of insulinomas and correlated with MSI-H (P = 0.008). Promoter methylation and loss of heterozygosity of MLH1 gene was found in 31 and 49% of insulinomas, respectively. Reduced expression of MLH1 and MSI-H were significantly associated with both tumor malignancy (P = 0.033 and P = 4.8 x 10(-6), respectively) and incurable disease (P = 0.006 and P = 0.001, respectively). CONCLUSION: High frequency of MSI occurred in sporadic insulinomas. The silencing of MLH1 gene may partially contribute to the MSI-H in the tumors. Assessing MSI-H and expressions of MLH1 could be used to distinguish benign and malignant insulinomas and to predict the outcome of patients.

Evaluating the role of serum elastase 1 in the diagnosis of pancreatic cancer.

OBJECTIVE: To determine the normal value of serum elastase 1 in Chinese adults and evaluate its diagnostic value for pancreatic cancer. METHODS: Serum elastase 1 and CA19-9 were measured in 132 samples, including 39 patients with pancreatic cancer, 48 with other gastrointestinal malignancy, 24 with gastrointestinal benign disease and 21 healthy adults as normal control. Multiple statistical methods including receiver operating characteristics curve and discriminant analysis were employed. RESULTS: The established normal range of serum elastase 1 in Chinese adults was found to be under 4.36 mg/L. Serum elastase 1 increased markedly in patients with pancreatic carcinoma of smaller size and/or located in the pancreatic head. The sensitivity, specificity and overall accuracy of elastase 1 for diagnosis of pancreatic cancer were 61.5%, 75.3% and 71.2%, respectively, as compared with 71.8%, 73.1% and 72.7% for CA19-9. Discriminant analysis can improve the sensitivity and overall accuracy of elastase 1 to 82.0% and 74.2%, respectively, with a slight decline in the specificity to 71.0%. CONCLUSIONS: The cutoff value of serum elastase 1 in normal Chinese adults is 4.36 mg/L. Serum elastase 1 is effective in the diagnosis of pancreatic cancer, especially for those of smaller size or in the pancreatic head. Use of appropriate statistical methods can help to make the diagnosis more accurate.