Endocrine tumors of the pancreas: Ki-67 immunoreactivity on paraffin sections is an independent predictor for malignancy: a comparative study with proliferating-cell nuclear antigen and progesterone receptor protein immunostaining, mitotic index, and other clinicopathologic variables

Establishment of patient derived xenografts as functional testing of lung cancer aggressiveness

Despite many years of research efforts, lung cancer still remains the leading cause of cancer deaths worldwide. Objective of this study was to set up a platform of non-small cell lung cancer patient derived xenografts (PDXs) faithfully representing primary tumour characteristics and offering a unique tool for studying effectiveness of therapies at a preclinical level. We established 38 PDXs with a successful take rate of 39.2%. All models closely mirrored parental tumour characteristics although a selective pressure for solid patterns, vimentin expression and EMT was observed in several models. An increased grafting rate for tumours derived from patients with worse outcome (p = 0.006), higher stage (p = 0.038) and higher CD133⁺/CXCR4⁺/EpCAM⁻ stem cell content (p = 0.019) was observed whereas a trend towards an association with SUV_max higher than 8 (p = 0.084) was detected. Kaplan Meier analyses showed a significantly worse (p = 0.0008) overall survival at 5 years in patients with grafted vs not grafted PDXs also after adjusting for tumour stage. Moreover, for 63.2% models, grafting was reached before clinical recurrence occurred. Our findings strengthen the relevance of PDXs as useful preclinical models closely reflecting parental patients tumours and highlight PDXs establishment as a functional testing of lung cancer aggressiveness and personalized therapies.

Evaluation of treatment for rectal neuroendocrine tumors sized under 20 mm in comparison with the WHO 2010 guidelines

Rectal neuroendocrine tumor (NET) is a relatively rare lesion of the gastrointestinal tract, but the prospective examination with colonofiberoscopy or endoscopic ultrasound has increased the frequency of its detection. It is often difficult to determine the optimal treatment for NETs sized <20 mm in the clinical setting. Other clinicopathological variables are not considered in the current guidelines and staging systems. Although the effects of lymphovascular invasion are not covered by the World Health Organization (WHO) 2010 guidelines or tumor-node-metastasis (TNM) staging system, this may be promising for the establishment of improved guidelines and staging systems, particularly for early-stage colorectal carcinoids. The aim of the present study was to evaluate rectal NETs sized <20 mm in comparison with the WHO 2010 guidelines. Between January 2005 and December 2013, 40 consecutive patients [26 men and 14 women; median age, 59.3 years (range, 34-81 years)] who underwent endoscopic resection of rectal NETs, and 12 patients undergoing surgical resection of rectal NETs, were enrolled in this retrospective study. The median tumor size was 7.4 mm (range, 3-15 mm). The locations of the NET were the rectosigmoid colon (n=3), the upper rectum (n=13), and the lower rectum (n=25). The NETs were classified by size as 0-5 (n=7), 6-10 (n=29) and 11-15 mm (n=4). The surgical procedures performed included low anterior resection plus esophagectomy (n=1), laparoscopic low anterior resection (n=7) and laparoscopic intersphincteric resection (n=4). Only 1 patient had lymph node metastasis (tumor sized 6-10 mm, with lymphovascular invasion). NET recurrence was not detected in any of the patients. According to the WHO guidelines, the tumors were classified as grade (G)1 (n=8), G2 (n=3) and G1/G2 (n=1). The tumor in the patient with lymph node metastasis was G1. NETs sized <10 mm may be curatively treated by endoscopic resection. However, NETs with either lymphovascular invasion or sized >1 cm carry a risk for metastasis equivalent to that of adenocarcinomas. Therefore, it is mandatory to histologically examine lymphovascular invasion in specimens retrieved via endoscopic resection to determine the necessity for further radical surgery with regional lymph node dissection. The treatment of NETs sized <20 mm as presently defined in the WHO 2010 guidelines requires further evaluation.

Loss of Progesterone Receptor Expression Is an Early Tumorigenesis Event Associated with Tumor Progression and Shorter Survival in Pancreatic Neuroendocrine Tumor Patients

Background

Pancreatic neuroendocrine tumors (PanNETs) are the second most common pancreatic neoplasms and there is no well-elucidated biomarker to stratify their detection and prognosis. Previous studies have reported that progesterone receptor (PR) expression status was associated with poorer survival in PanNET patients.

Methods

To validate previous studies, PR protein expression was assessed in 21 neuroendocrine microadenomas and 277 PanNETs and compared with clinicopathologic factors including patient survival.

Results

PR expression was gradually decreased from normal islets (49/49 cases, 100%) to neuroendocrine microadenoma (14/21, 66.6%) to PanNETs (60/277, 21.3%; p < .001). PanNETs with loss of PR expression were associated with increased tumor size (p < .001), World Health Organization grade (p = .001), pT classification (p < .001), perineural invasion (p = .028), lymph node metastasis (p = .004), activation of alternative lengthening of telomeres (p = .005), other peptide hormonal expression (p < .001) and ATRX/DAXX expression (p = .015). PanNET patients with loss of PR expression (5-year survival rate, 64.1%) had significantly poorer recurrence-free survival outcomes than those with intact PR expression (90%) by univariate (p = .012) but not multivariate analyses. Similarly, PanNET patients with PR expression loss (5-year survival rate, 76%) had significantly poorer overall survival by univariate (p = .015) but not multivariate analyses.

Conclusions

Loss of PR expression was noted in neuroendocrine microadenomas and was observed in the majority of PanNETs. This was associated with increased grade, tumor size, and advanced pT and pN classification; and was correlated with decreased patient survival time by univariate but not multivariate analyses. Loss of PR expression can provide additional information on shorter disease-free survival in PanNET patients.

Ki-67 labeling index of neuroendocrine tumors of the lung has a high level of correspondence between biopsy samples and surgical specimens when strict counting guidelines are applied

Optimal histopathological analysis of biopsies from metastases of neuroendocrine tumor (NET) of the lung requires more than morphology only. Additional parameters such as Ki-67 labeling index are required for adequate diagnosis, but few studies have compared reproducibility of different counting protocols and modalities of reporting on biopsies of lung NET. We compared the results of four different manual counting techniques to establish Ki-67 LI. On 47 paired biopsies and surgical specimens from 22 typical carcinoids (TCs), 14 atypical carcinoids (ACs), six large cell neuroendocrine carcinomas (LCNECs), and five small cell carcinomas (SCCs) immunohistochemical staining of Ki-67 antigen was performed. We counted, in regions of highest nuclear staining (HSR), a full ×40-high-power field (diameter = 0.55 mm), 500 or 2000 cells, or 2 mm² surface area, including the HSR or the entire biopsy fragment(s). Mitoses and necrosis were evaluated in an area of 2 mm² or the entire biopsy fragment(s). Between the four counting methods, no differences in Ki-67 LI were observed. However, a Ki-67 LI higher than 5% was found in only four cases when in an HSR, 500 cells were counted (18%), five (23%) when in an HSR 2000 cells were counted, four (18%) when 2 mm² were counted, and one (5%) TC case when the entire biopsy was counted. A 20% cutoff distinguished TC and AC from LCNEC and SCC with 100% specificity and sensitivity, while mitoses and necrosis failed to a large extent. Ki-67 LI in biopsy samples was concordant with that in resection specimens when 2000 cells, 2 mm², or the entire biopsy fragment(s) were counted. Our results are important for clinical management of patients with metastases of a lung NET.

A Novel Nomogram to Predict the Prognosis of Patients Undergoing Liver Resection for Neuroendocrine Liver Metastasis: an Analysis of the Italian Neuroendocrine Liver Metastasis Database

Even though surgery remains the only potentially curative option for patients with neuroendocrine liver metastases, the factors determining a patient's prognosis following hepatectomy are poorly understood. Using a multicentric database including patients who underwent hepatectomy for NELMs at seven tertiary referral hepato-biliary-pancreatic centers between January 1990 and December 2014, we sought to identify the predictors of survival and develop a clinical tool to predict patient's prognosis after liver resection for NELMs. The median age of the 238 patients included in the study was 61.9 years (interquartile range 51.5-70.1) and 55.9 % (n = 133) of patients were men. The number of NELMs (hazard ratio = 1.05), tumor size (HR = 1.01), and Ki-67 index (HR = 1.07) were the predictors of overall survival. These variables were used to develop a nomogram able to predict survival. According to the predicted 5-year OS, patients were divided into three different risk classes: 19.3, 55.5, and 25.2 % of patients were in low (>80 % predicted 5-year OS), medium (40-80 % predicted 5-year OS), and high (<40 % predicted 5-year OS) risk classes. The 10-year OS was 97.0, 55.9, and 20.0 % in the low, medium, and high-risk classes, respectively (p < 0.001). We developed a novel nomogram that accurately (c-index >70 %) staged and predicted the prognosis of patients undergoing liver resection for NELMs.

Increased Activity of the Immunoregulatory Enzyme Indoleamine-2,3-Dioxygenase with Consecutive Tryptophan Depletion Predicts Death in Patients with Neuroendocrine Neoplasia

BACKGROUND/AIMS

Data from a considerable number of malignancies demonstrate that depletion of the essential amino acid tryptophan via induction of the immunoregulatory enzyme indoleamine-2,3-dioxygenase (IDO) serves as an important tumour escape strategy and is of prognostic importance. Here we investigate the predictive value of the activity of IDO as well as levels of tryptophan and respective downstream catabolites in a large cohort of patients with neuroendocrine neoplasms (NEN).

METHODS

142 consecutive Caucasian patients (62 male, aged 60.3 ± 11.9 years) with histologically confirmed NEN were systematically analysed in a retrospective blinded end point analysis. Patients were followed up for a mean period of about 3.9 ± 1.9 years. Clinical outcome, levels of established biomarkers, and tryptophan degradation markers (assessed using tandem mass spectrometry) including estimated IDO activity were recorded. Cox proportional hazards regression models were performed for the assessment of prognostic power.

RESULTS

We found that baseline tryptophan levels were significantly lower and IDO activity was significantly increased in non-survivors. The risk for death inclined stepwise and was highest in patients in the upper tertile of IDO activity. Cox proportional regression models identified IDO activity as an independent predictor of death.

CONCLUSIONS

In this retrospective analysis, we observed that baseline activity of the immunoregulatory enzyme IDO was significantly increased in non-survivors. IDO activity was identified as an independent predictor of death in this cohort of NEN patients. Whether IDO activity or tryptophan depletion serves to guide future therapeutic interventions in NEN remains to be established.

The ENETS/WHO grading system for neuroendocrine neoplasms of the gastroenteropancreatic system: a review of the current state, limitations and proposals for modifications

The understanding of neuroendocrine neoplasms has evolved significantly since their initial descriptions in the 1800s to early 1900s. In the gastroenteropancreatic system, this group of malignant tumors is subdivided into well and poorly differentiated neuroendocrine neoplasms based on morphologic, proliferative and biologic differences. However, it has become increasingly apparent that well-differentiated neuroendocrine tumors are not a homogeneous group. Attempting to better predict outcome of these tumors has been the motivation behind numerous proposed classification systems, the evolution of which culminated with the currently used system, the ENETS/WHO classification. Herein, we review the genesis of this classification system and some of its shortcomings. In addition, we discuss some of the most recent proposals that suggest modifications to the current system.

Histopathology of NET: Current concepts and new developments

The diagnosis of neuroendocrine tumors is based on their histopathologic appearance and immunohistochemical profile. With the WHO 2010 classification formal staging and grading was introduced for gastro-entero-pancreatic NET, however, the nomenclature for lung neuroendocrine tumors still relies on the carcinoid term. In this review we also focus on the situation of neuroendocrine carcinoma of unknown primary, tissue biomarkers and actual controversies in the histopathology of NEN.

Features Associated With Metastases Among Well-Differentiated Neuroendocrine (Carcinoid) Tumors of the Appendix: The Significance of Small Vessel Invasion in Addition to Size

BACKGROUND

The risk of metastatic disease among carcinoid tumors of the appendix increases with tumor size. However, it is unclear if any features other than size are also associated with an increased risk of metastatic disease.

OBJECTIVE

The aim of this study was to review the characteristics of appendiceal carcinoid tumors and determine if other histologic features besides size should guide surgical decision making.

DESIGN

This study involved a retrospective case series.

SETTINGS

This study was conducted at a single tertiary acute care hospital.

PATIENTS

Patients diagnosed with an appendiceal carcinoid tumor between 2000 and 2014 were identified. Goblet cell carcinoids, adenocarcinomas with neuroendocrine features, and tumors from other primary locations were excluded.

INTERVENTIONS

Simple appendectomy or segmental/total colectomy with lymphadenectomy was performed.

MAIN OUTCOME MEASURES

The primary outcomes measured were metastases, recurrence, and overall survival.

RESULTS

Seventy-nine patients were included. The overall incidence of metastatic disease was 10%. Patients with metastatic disease were more likely to be male (75% vs 28%, p = 0.008), have small-vessel invasion (43% vs 5%, p = 0.001), and have larger tumors (median 2.0 cm vs 0.5 cm, p < 0.001). Among tumors <2 cm, the incidence of metastases among tumors with small-vessel invasion was 60% compared with 0% among those without small-vessel invasion (p < 0.001). Among tumors ≥2 cm, the incidence of metastases was 50% irrespective of small-vessel invasion. If small-vessel invasion was used as a second indication for performing a right hemicolectomy along with size ≥2 cm, both the sensitivity and negative predictive value would have been 100% compared with 63% and 96% if size was used alone. Patients with metastatic disease had a higher incidence of recurrence (13% vs 0%, p = 0.003), but overall survival was 100% in both groups.

LIMITATIONS

Small sample size, retrospective design, and limited long-term follow-up were the limitations of this study.

CONCLUSIONS

Carcinoid tumors of the appendix <2 cm with small-vessel invasion have similar metastatic potential as tumors ≥2 cm. Therefore, a recommendation for a right hemicolectomy should be considered for tumors <2 cm with small-vessel invasion. Additional prospective multicenter studies are warranted.

What clinicians are asking pathologists when dealing with lung neuroendocrine neoplasms?

Lung neuroendocrine tumors (NET) are currently classified in resection specimens according to four histological categories, namely typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Diagnostic criteria have remained unchanged in the 2015 WHO classification, which has ratified the wide acceptance and popularity of such terminology in the pathologists׳ and clinicians׳ community. A unifying umbrella of NE morphology and differentiation has been recognized in lung NET, which has pushed to enter an unique box of invasive tumors along with diffuse idiopathic pulmonary NE cell hyperplasia (DIPNECH) as a pre-invasive lesion with a potential toward the development of carcinoids. However, uncertainties remain in the terminology of lung NET upon small samples, where Ki-67 antigen could play some role to avoid misdiagnosing carcinoids as high-grade NE tumors. Epidemiologic, clinical and genetic traits support a biological three-tier over a pathology four-tier model, according to which TC are low malignancy tumors, AC intermediate malignancy tumors and LCNEC/SCC high malignancy tumors with no significant differences in survival among them. Inconsistencies in diagnostic reproducibility, troubles in the therapy of AC and LCNEC, and limitations to histology within the same tumor category argue in favor of a global re-thinking of lung NET where a grading system could play a role. This review outlines three main key questions in the field of lung NET: (A) unbiased diagnoses, (B) the role of Ki-67 and tumor grading, and (C) management of predictive markers. Answers are still inconclusive, thus additional research is required to improve our understanding on lung NET.

Interlaboratory variability of MIB1 staining in well-differentiated pancreatic neuroendocrine tumors

Neuroendocrine tumors (NET) are routinely graded and staged to judge prognosis. Proliferation index using MIB1 staining has been introduced to assess grading. There are vivid discussions on cutoff definitions, automated counting, and interobserver variability. However, no data exist regarding interlaboratory reproducibility for low proliferation indices which are of importance to discriminate between G1 and G2 NET. We performed MIB1 staining in three different university hospital-based pathology laboratories on a tissue micro array (TMA) of a well-characterized patient cohort, containing pancreatic NET of 61 patients. To calculate the proliferation index, number of positive tumor nuclei was divided by the total number of tumor nuclei. Labeling index was compared to mitotic counts in whole tissue sections and to clinical outcome. Linear regression analysis, intraclass comparison, and log-rank analysis were performed. Intraclass correlation showed moderate-to-fair agreement. Especially low proliferating tumors were affected by interlaboratory differences. Log-rank analysis was performed for each lab and resulted in three different cutoffs (5.0, 3.0, and 0.5 %). Every calculated cutoff stratified the patient cohort to a significant extent for the underlying stain (p < 0.001, <0.001, and <0.001) but showed no or lesser significance when applied to the other stains. Significant and relevant interlab differences for MIB1 exist. Since the MIB1 proliferation index influences grading, local cutoffs or external standardization should urgently be introduced to achieve reliability and reproducibility.

Long-term outcomes and prognostic factors in 78 Japanese patients with advanced pancreatic neuroendocrine neoplasms: a single-center retrospective study

OBJECTIVE

Despite an increase in the number of Japanese patients with pancreatic neuroendocrine neoplasms, long-term outcomes and prognostic factors, especially for those with advanced disease, remain unclear.

METHODS

We retrospectively reviewed the medical records of 78 patients with unresectable pancreatic neuroendocrine neoplasms treated at our hospital from January 1987 to March 2015. Survival analyses were performed using Kaplan-Meier methods. Prognostic significance of several clinicopathological factors were analyzed by univariate and multivariate analyses using a Cox regression model.

RESULTS

Median overall survivals of pancreatic neuroendocrine tumor (n = 64) and pancreatic neuroendocrine carcinoma (n = 14) were 83.7 and 9.1 months, respectively (hazard ratio: 0.02, 95% confidence interval: 0.01-0.08, P < 0.001). Although no significant differences were observed using a Ki-67 cut-off value of 2% (hazard ratio: 0.46, 95% confidence interval: 0.16-1.13, P = 0.0989), a Ki-67 cut-off of 10% was a significant predictor in patients with pancreatic neuroendocrine tumor (hazard ratio: 9.95, 95% confidence interval, 3.01-32.97, P < 0.001). Treatment after the advent of targeted therapy (hazard ratio: 0.07, 95% confidence interval: 0.03-0.19, P < 0.001) and the presence of bone metastases (hazard ratio: 4.38, 95% confidence interval: 1.42-11.29, P = 0.013) were significant prognostic factors in patients with pancreatic neuroendocrine tumor evaluated by univariate analysis. Multivariate analysis also revealed that a Ki-67 index ≥10% (hazard ratio: 38.8, 95% confidence interval: 8.42-226.62, P < 0.001), approval of targeted therapy (hazard ratio: 0.02, 95% confidence interval: 0.00-0.11, P < 0.001) and bone metastases (hazard ratio: 5.56, 95% confidence interval: 1.10-24.00, P = 0.039) were independent prognostic factors.

CONCLUSIONS

We elucidated the long-term outcomes and prognostic factors in Japanese patients with advanced pancreatic neuroendocrine neoplasms.

High Ki67 expression is an independent good prognostic marker in colorectal cancer

AIMS

To correlate Ki67 expression with outcome in colorectal cancer (CRC).

METHODS

Ki67 labelling index (Ki67LI) was analysed by immunohistochemistry on a tissue microarray containing 1800 CRCs. The results were compared with clinicopathological and molecular parameters.

RESULTS

Ki67LI was considered low in 26.3%, moderate in 56.7% and high in 17.0% of 1653 interpretable CRCs. High Ki67 expression was associated with low tumour stage (p<0.0001) and nodal status (p=0.0315), but not with tumour grade (p=0.8639), histological tumour type (p=0.1542) or tumour localisation, and was an independent prognosticator of favourable survival (p=0.0121). High Ki67 expression was also significantly associated with high-level nuclear β-catenin and p53 expression (p<0.0001 and p=0.0095, respectively).

CONCLUSIONS

In summary, our data show that high Ki67 expression in CRCs is associated with good clinical outcome. Ki67, p53 and β-catenin overexpression seem to be linked to CRC, and indicate a cellular state of high proliferative activity. Finally, our findings strongly argue for a clinical utility of Ki67 immunostaining as an independent prognostic biomarker in CRC.

Neuroendocrine Carcinomas of the Gastroenteropancreatic System: A Comprehensive Review

To date, empirical literature has generally been considered lacking in relation to neuroendocrine carcinomas (NECs), the highly malignant subgroup of neuroendocrine neoplasms. NECs are often found in the lungs or the gastroenteropancreatic (GEP) system and can be of small or large cell type. Concentrating on GEP-NECs, we can conclude that survival times are poor, with a median of only 4–16 months depending on disease stage and primary site. Further, this aggressive disease appears to be on the rise, with incidence numbers increasing while survival times are stagnant. Treatment strategies concerning surgery are often undecided and second-line chemotherapy is not yet established. After an analysis of over 2600 articles, we can conclude that there is indeed more empirical literature concerning GEP-NECs available than previously assumed. This unique review is based on 333 selected articles and contains detailed information concerning all aspects of GEP-NECs. Namely, the classification, histology, genetic abnormalities, epidemiology, origin, biochemistry, imaging, treatment and survival of GEP-NECs are described. Also, organ-specific summaries with more detail in relation to disease presentation, diagnosis, treatment and survival are presented. Finally, key points are discussed with directions for future research priorities.

Tumor-associated macrophages are a useful biomarker to predict recurrence after surgical resection of nonfunctional pancreatic neuroendocrine tumors

OBJECTIVE

Patients with nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) have poorer survival than those with functional PNETs. Our objective was to identify risk factors for recurrence after resection to better define surveillance parameters to improve long-term outcomes.

METHODS

A retrospective analysis was performed for NF-PNET patients who underwent resection at the University of Michigan from 1995 to 2012. Immunohistochemical staining of tissues from patients with and without disease recurrence was performed for Ki-67 and the macrophage marker CD68, as tumor-associated macrophages are important for PNET development and progression. Clinicopathological factors and patient outcomes were measured.

RESULTS

Ninety-seven NF-PNET patients underwent surgical resection. There was a recurrence rate of 14.4% (14/97). The median time to recurrence was 0.61 years, with 10 (71%) patients recurring within the first 2 years. Six of 7 patients (86%) monitored at 6-month surveillance intervals were diagnosed with recurrence on their first computed tomographic scan or during the intervening intervals. By Cox proportional hazards analysis, the most significant independent risk factors for recurrence were higher grade, stage, and intraoperative blood loss. High CD68 score and Ki-67 index correlated with recurrence risk, and Ki-67 index inversely correlated with time to recurrence. In patients who otherwise had few risk factors, a high CD68 score was a significant prognostic factor for recurrence.

CONCLUSIONS

In patients with NF-PNETs, risk factors associated with recurrence were high EBL, grade, stage, CD68 score, and Ki-67 index. The CD68 score was an important prognostic factor in patients who otherwise had few clinicopathological risk factors; therefore, the CD68 score should be considered when planning surveillance strategies. We recommend that NF-PNET patients at high risk of recurrence undergo initial surveillance every 3 months for 2 years after surgery.

Cytological Ki-67 in pancreatic endocrine tumors: a new "must"?

In the last decades, the incidence of neuroendocrine tumors (NETs) has been rising and this might be due to more awareness, improved diagnostic tools and a change in definition. The histopathological type of the tumor, its Ki-67 or MIB-1 proliferation index, size and location, as well as the age of the patient, seems to be the most important factor that affects prognosis and survival. In 2008, in one of our studies, we concluded that the cytological Ki-67 may improve the preoperative assessment of pancreatic NETs (pNETs), helping the clinician choosing the optimal therapeutical approach". Although the literature reports discordant opinions on the value of tumor proliferation markers in predicting a patient's prognosis, many studies have then reinforced the idea that Ki-67 expression in histological sections obtained from pNETs is an important predictor of their biological behaviour. The WHO classification of pNETs includes Ki-67 expression in the list of parameters (together with distant metastases, organ infiltration, dimension, angio/neuroinvasion, number of mitosis) determining the patient's prognosis. In conclusion we think that any study aimed to assess the correct biology and proliferative pattern of NETs contributes to the already known but still unclear attempt to define the correct individualized therapeutic strategy for each patient before surgery or any other therapeutic approach.

Ki-67 antigen in lung neuroendocrine tumors: unraveling a role in clinical practice

Classification of lung neuroendocrine (NE) tumors is a step-wise process with four tumor categories being identified by morphology, namely typical carcinoid (TC), atypical carcinoid, large-cell NE carcinoma, and small-cell lung carcinoma (SCLC). Ki-67 antigen or protein (henceforth simply Ki-67) has been largely studied in these tumors, but the clinical implications are so far not clear. A well-defined role has regarded the diagnostic use in the separation of TC and AC from SCLC in nonsurgical specimens, with monoclonal antibody MIB-1 resulting in the most used reagent after antigen retrieval procedures. Uncertainties, however, have arisen in its assessment, usually expressed as Ki-67 labeling index, because of some variability in obtaining either value of the fraction. A diagnostic role is currently lacking, even though there are significant differences in most cases between TC and AC, less so between large-cell NE carcinoma and SCLC. In addition, the prognostic role of Ki-67 is debated, likely due to methodological and biological reasons. The last challenge would be to identify an effective lung-specific grading system based on Ki-67 labeling index. In this review article, five relevant issues to Ki-67 have been addressed by using a question-answer methodology, with relevant key points discussing major interpretation issues. The conclusion is that Ki-67 is a feasible and potentially meaningful marker in lung NE tumors, but more data are needed to determine its ideal function in this setting of tumors.

Expression of estrogen-induced genes and estrogen receptor β in pancreatic neuroendocrine tumors: implications for targeted therapy

OBJECTIVE

The indolent nature and expression of progesterone receptor (PR), a well-known estrogen-induced gene, in a subset of pancreatic neuroendocrine tumors (PanNETs), raise the possibility of hormonal regulation in these tumors.

METHODS

Immunohistochemical expression of estrogen receptors (ERs) α and β as well as messenger RNA expression of estrogen-induced genes (PR, EIG121, IGF-1, IGF-1R, sFRP1, and sFRP4) by quantitative reverse transcription-polymerase chain reaction were examined in 131 World Health Organization grade G1 and G2 PanNETs and correlated their expression with clinicopathological features.

RESULTS

Thirty-nine PanNETs (30%) showed high positive ERβ staining, and 87 cases (66%) had low positive ERβ staining; only 5 cases (4%) had no nuclear staining. Pancreatic neuroendocrine tumors with small size (P = 0.02), low World Health Organization grade (P = 0.02), and low American Joint Committee on Cancer stage (P = 0.006) more frequently showed high positive ERβ staining. Among the estrogen-induced genes studied, PanNETs had significantly higher expression of PR, EIG121, IGF-1, sFRP1, and sFRP4 compared with normal pancreas, independent of age or sex. High positive ERβ staining was associated with an increased expression of PR (P < 0.001) and EIG121 (P = 0.02).

CONCLUSIONS

Our study showed that PanNETs with favorable prognostic features have higher ERβ expression, which is associated with up-regulated PR and EIG121 messenger RNA expression. Estrogen regulation in PanNETs could potentially help in risk stratification and provide a rational target for novel treatment strategies.

Progesterone receptor and PTEN expression predict survival in patients with low- and intermediate-grade pancreatic neuroendocrine tumors

CONTEXT

The PI3K-AKT-mTOR (phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin) pathway plays a crucial role in a subset of advanced pancreatic neuroendocrine tumors (PanNETs). In breast and endometrial carcinoma, activation of this pathway inhibits progesterone receptor (PR) expression.

OBJECTIVE

To determine whether combined low expression of PR and phosphatase and tensin homologue (PTEN), a negative regulator of the PI3K-AKT-mTOR pathway, is a prognostic factor.

DESIGN

A total of 160 resected PanNETs (89 low grade and 71 intermediate grade) were analyzed for PR and PTEN immunohistochemical positivity and staining was correlated with metastasis-free survival (MFS) and overall survival (OS). Progesterone receptor staining was scored as positive by using 1% or greater as cutoff. Weak/faint staining in greater than 90% of tumor cells was considered low PTEN positivity.

RESULTS

Most PanNETs (110 cases, 69%) were both PR and PTEN positive, 45 (28%) were either PR or PTEN positive, and only 5 (3%) had a PR-negative and PTEN-low profile. Combined PR-PTEN positivity was significantly associated with MFS in patients with stage I and II disease (P <.001) and OS in all patients (P < .001) and remained a significant predictor of survival after adjusting for other factors. Patients with PR-negative-PTEN-low PanNETs had the shortest median MFS and OS, compared to those with tumors that were either PR or PTEN positive and with tumors positive for both PR and PTEN (P ≤ .001).

CONCLUSION

Combined immunohistochemical assessment of PR and PTEN may help identify a small subset of PanNETs with more aggressive behavior and may aid in risk stratification.

Elevated Ki-67 labeling index in 'synchronous liver metastases' of well differentiated enteropancreatic neuroendocrine tumor

There is no consensus as to whether or not metastatic nodules in the liver should be biopsied for tumor grading in cases of neuroendocrine tumors with 'synchronous liver metastasis'. In this study, we compared the Ki-67 labeling index between the primary tumor and synchronous liver metastasis in 30 patients, who had received simultaneous resections. Examined tumors were of the small bowel (n = 18) or pancreas (n = 12), and G1 or G2 in primary histologic grade. In 20 patients (67%), the Ki-67 index was similar between the primary tumor and liver metastasis, but 10 (33%) showed an elevation of 3.4-14.4% in the liver, which increased the tumor grade in 4 cases. The Ki-67 elevation in the liver was more common in G2 than G1 neoplasms (P = 0.002). The size, but not number, of liver metastases was significantly larger in patients with an elevated Ki-67 index (P = 0.006). Using 40 mm as a provisional cutoff for the greatest diameter of liver metastases, the positive predictive value of this discriminator for elevated Ki-67 was 56%, and the negative predictive value was 93%. In conclusion, synchronous liver metastases can yield a higher Ki-67 labeling index than primary neuroendocrine tumours, particularly when the secondary is greater than 40 mm.

Variability of Ki67 labeling index in multiple neuroendocrine tumors specimens over the course of the disease

BACKGROUND

The Ki67-LI is a valid surrogate for biologic behavior of neuroendocrine tumors (NETs), with higher levels associated with aggressive behavior. The World Health Organization (WHO) classifies NETs according to Ki67-LI (G1: <3%; G2 : 3-20%; G3: >20%). Little is known about the evolution of NETs histologic characteristics over the disease course. We sought to evaluate variations in Ki67-LI throughout NETs disease course.

METHODS

We retrospectively reviewed the Sunnybrook Odette Cancer Center NET database for patients with multiple pathology specimens. Primary outcome was the WHO NET class based on Ki67-LI for each specimen. We assessed change in WHO class between specimens.

RESULTS

Forty-three patients were retrieved, of which 39 had specimens from the primary tumor and a metastatic focus, and 4 had specimens from multiple metastatic foci. Sixteen (37.0%) were identified with Ki67-LI falling in different WHO classes on distinct biopsies. For 12 (75.0%) of those 16 patients, Ki67-LI showed enough variability for WHO class to be upstaged: 5 (31%) from G1 to G2, 2 (13%) from G2 to G3, and 5 (31%) from G1 to G3.

CONCLUSION

When multiple pathology specimens were available, Ki67-LI varied throughout NETs disease course, with a majority of cases upgraded to a higher WHO class. If confirmed, this finding may have implications in how neuroendocrine tumors are monitored and treated. Further research is warranted to confirm these findings, understand better the underlying mechanisms of Ki67 variability, and define its relationship to prognosis.

Unraveling tumor grading and genomic landscape in lung neuroendocrine tumors

Currently, grading in lung neuroendocrine tumors (NETs) is inherently defined by the histological classification based on cell features, mitosis count, and necrosis, for which typical carcinoids (TC) are low-grade malignant tumors with long life expectation, atypical carcinoids (AC) intermediate-grade malignant tumors with more aggressive clinical behavior, and large cell NE carcinomas (LCNEC) and small cell lung carcinomas (SCLC) high-grade malignant tumors with dismal prognosis. While Ki-67 antigen labeling index, highlighting the proportion of proliferating tumor cells, has largely been used in digestive NETs for assessing prognosis and assisting therapy decisions, the same marker does not play an established role in the diagnosis, grading, and prognosis of lung NETs. Next generation sequencing techniques (NGS), thanks to their astonishing ability to process in a shorter timeframe up to billions of DNA strands, are radically revolutionizing our approach to diagnosis and therapy of tumors, including lung cancer. When applied to single genes, panels of genes, exome, or the whole genome by using either frozen or paraffin tissues, NGS techniques increase our understanding of cancer, thus realizing the bases of precision medicine. Data are emerging that TC and AC are mainly altered in chromatin remodeling genes, whereas LCNEC and SCLC are also mutated in cell cycle checkpoint and cell differentiation regulators. A common denominator to all lung NETs is a deregulation of cell proliferation, which represents a biological rationale for morphologic (mitoses and necrosis) and molecular (Ki-67 antigen) parameters to successfully serve as predictors of tumor behavior (i.e., identification of pathological entities with clinical correlation). It is envisaged that a novel grading system in lung NETs based on the combined assessment of mitoses, necrosis, and Ki-67 LI may offer a better stratification of prognostic classes, realizing a bridge between molecular alterations, morphological features, and clinical behavior.

Investigation and management of pancreatic tumours

Pancreatic cancer is the 10th most commonly diagnosed cancer in the UK and the fifth most common cause of cancer death. It remains one of the most aggressive cancers with over 95% of patients affected dying of their disease. Often presenting at an advanced stage of disease progression, there is currently no simple screening test available. Therefore a high clinical suspicion and prompt appropriate investigation is required from physicians when dealing with patients with symptoms in keeping with pancreatic cancer. The gastroenterology 2010 curriculum states that trainees should learn the presentation and multidisciplinary management of patients with pancreatic tumours. In this article we discuss the typical clinical presentations of common and less common pancreatic tumours followed by the investigation, staging and management required.

Grading of neuroendocrine neoplasms: mitoses and Ki-67 are both essential

BACKGROUND

The current WHO classification for neuroendocrine neoplasms (NEN) of the gastrointestinal tract requires Ki-67 and mitotic index for grading. However, both indexes might be conflicting as far as grade is concerned. In this study, we investigate which of the two indexes is most informative to predict survival.

METHODS

We assessed 362 patients with NEN of gastrointestinal (n = 148), pancreatic (n = 29), lung (n = 77), unknown primary site (n = 102) and of miscellaneous (n = 6) origin. Follow-up and proliferative indexes were recorded.

RESULTS

Survival was clearly correlated with both proliferative indexes (p < 0.001). One hundred and nineteen samples (34%) showed discordance in grading between the Ki-67 and the mitotic index, of which 74 (62%) were biopsies and 45 (38%) resection specimens (p = 0.001). In 86% of these cases, survival matched with the highest proliferative index, which was the Ki-67 index in 87% of these cases. Seventeen cases had a mitotic index of 2 (threshold grade 2) and a Ki-67 index of <3% (grade 1). For these cases, survival curve matched that of patients with concordant indexes of grade 1.

CONCLUSION

Grading NEN using two proliferative markers results in discordance between these indexes in one third of cases, more often in biopsy material than in resection specimens. If results are discordant, survival is for the most part associated with the grade of the highest index, for the most part Ki-67. Thus, grading with two proliferative indexes is useful as it highlights cases where one of these indexes may be incongruent.

Reliability of proliferation assessment by Ki-67 expression in neuroendocrine neoplasms: eyeballing or image analysis?

BACKGROUND

The latest WHO classification for neuroendocrine neoplasms (NEN) of the gastrointestinal tract defines grade according to Ki-67 and mitotic indices. Some have questioned the reproducibility and thus the reliability of Ki-67 assessment. We therefore investigated the accuracy of this proliferation marker in NEN.

METHODS

The Ki-67 index of tumor specimens of NEN (n = 73) was assessed by two pathologists as in routine practice with eyeballing and twice by image analysis using ImageJ freeware at different magnifications. RESULTS were correlated with overall survival.

RESULTS

The intraclass correlation coefficient (ICC) between pathologists was 0.88. The ICC for the measurements using image analysis was 0.85. The ICC between all four measurements (pathologists and ImageJ) was 0.80. If the Ki-67 index was translated to grade as prescribed by the current WHO classification (<3% = grade 1, 3-20% = grade 2, >20% = grade 3), kappa was between 0.61 and 0.75. Grades based on pathologist scoring were often (16-29%) higher than grades assigned by image analysis (p < 0.001). Grade was significantly correlated with survival (p < 0.0001) irrespective of the way Ki-67 was assessed.

CONCLUSION

Assessment of the Ki-67 index by eyeballing correlates remarkably well with the Ki-67 index as calculated by image analysis and is therefore an accurate parameter. Moreover, it is significantly related to survival irrespective of the method used. Yet if the Ki-67 index is translated to grade, the grade should be interpreted with caution due to values around threshold levels.

Gastroenteropancreatic neuroendocrine neoplasms: historical context and current issues

The digestive organs contain a large number of neuroendocrine cells as part of the diffuse neuroendocrine system. Neuroendocrine tumors can occur in every digestive organ. It has long been recognized that this is a diverse group of tumors with very different clinical outcomes; however, well-recognized prognostic parameters had been elusive until recently. Over the years, there have been several different classification schemes, each with different strengths and weaknesses. In an effort to standardize the classification and grading criteria for gastroenteropancreatic neuroendocrine tumors, the current World Health Organization classification includes a histologic grade based on proliferative rate (mitotic rate and Ki67 index) and a TNM stage that varies from organ to organ. The prognostic value of both the grade and stage has been validated in multiple studies. However, several issues remain, including the lack of standardized methods to assess proliferative rate, potential discrepancies between the mitotic count and the Ki67 index; intratumoral heterogeneity in proliferative rate; and the need for refinement in proliferative cut-points to define the grades. More studies are needed to further improve the classification of neuroendocrine tumors, thus guiding optimal treatment for these tumors.

Prognostic impact of diagnosing colorectal neuroendocrine carcinoma using the World Health Organization 2010 classification

BACKGROUND

Neuroendocrine carcinomas (NECs) arising in the large intestine are rare neoplasms with highly aggressive behavior. The aim of the study was to compare the 2000 and 2010 World Health Organization (WHO) classification of these colorectal NECs.

METHODS

We conducted a retrospective study of patients diagnosed with colorectal NECs according to the WHO 2000 classification who underwent surgery at the Asan Medical Center between May 2000 and December 2010. The data were reevaluated to assess their consistency with the WHO 2010 classification.

RESULTS

For 20 of the 34 patients (59%), the 2000 and 2010 WHO classifications yielded the same NEC diagnosis (NEC group), whereas for 14 of the 34 patients (41%), the WHO 2010 classification mandated a diagnosis of G1 or G2 neuroendocrine tumors (NETs) rather than NECs (G1/G2 NET group). The NEC group was older than the G1/G2 NET group (64 vs 55 years; P = .05). Tumor differentiation in the NEC group was poorer than in the G1/G2 NET group (percentage of poorly differentiated tumor, 70% vs 7%; P < .001). In both groups based on the 7th American Joint Committee on Cancer staging, most of the tumors were advanced at the time of diagnosis, reaching stage IIIB (6 NEC vs 10 NET) and stage IV (10 NEC vs 3 NET). The 5-year overall survival in the 2 groups was different (P = .02), but not the 5-year disease-free survival (P = .24).

CONCLUSION

These results indicate that the WHO 2010 classification of colorectal NEC is more accurate and has better prognostic value than the WHO 2000 classification.

Single institutional series of neuroendocrine tumors managed in the Australian Capital Territory

AIMS

Retrospective review of neuroendocrine tumors (NETs) treated within the Australian Capital Territory to describe the local epidemiology and assess prognostic clinicopathological factors.

METHODS

Patients with histologically proven non-pulmonary low to intermediate grade NETs were identified from our hospital clinical database. Data were analyzed according to epidemiological, clinical and histopathological characteristics.

RESULTS

Of the 107 included patients, the most common primary tumor site was jejunum/ileum (32%), followed by rectum (22%) and pancreas (11.2%). In total, 32% had distant metastases at presentation, most commonly in the liver. Most patients were symptomatic at diagnosis, while 22.4% of cases were found incidentally. Second malignancies, in particular of gastrointestinal origin, were diagnosed in 33.6%. Surgical debulking was the most common treatment (59.8%) while 18% had multimodality therapy. With a median follow-up of 25 months from diagnosis, about 78% of patients are still alive. Median time to first relapse was 15 months and the 5-year survival rate was 80% for NETs of jejunum/ileum. Univariate survival analysis revealed tumor location, high Ki67 index, raised plasma chromogranin A, and urine 5-hydroxyindoleacetic acid upon diagnosis to be associated with shorter 5-year survival.

CONCLUSION

The epidemiologic characteristics and long-term outcome in our series are comparable to other reported studies. This analysis presents some important prognostic factors which could be used for risk stratification in patients with NETs.

Phosphohistone H3 and Ki-67 labeling indices in cytologic specimens from well-differentiated neuroendocrine tumors of the gastrointestinal tract and pancreas: a comparative analysis using automated image cytometry

BACKGROUND

Ki-67 proliferation index was recently incorporated in the grading of neuroendocrine neoplasms (NENs) of the gastrointestinal tract (GIT) and pancreas. These are now divided into well-differentiated neuroendocrine tumors (WDNETs, grades 1 and 2) and poorly differentiated neuroendocrine carcinomas (grade 3). While Ki-67 is an established proliferation marker in NENs, phosphohistone H3 (PHH3), a newer marker of mitotic activity, is not.

METHODS

We determined Ki-67 and PHH3 indices on cytologic samples from WDNETs of the GIT and pancreas using an automated cellular imaging system (ACIS®).

RESULTS

There was a strong correlation between Ki-67 and PHH3 indices generated by ACIS on cytologic samples. However, in some cases the two stains caused conflicting grades within the same tumor.

CONCLUSION

Both antibodies stain cells in different phases of the cell cycle which may cause discordant grades, thus affecting patient management and prognostication. Ki-67 staining is stronger than PHH3, making 'hot spots' easier to identify on ACIS. Ki-67 is more ideal than PHH3 for staining NENs, especially in tumors with borderline grades. Because PHH3 generates lower mitotic indices it should not be used as a proliferation marker in NENs until its expression has been further characterized.

Preoperative assessment of nonfunctioning pancreatic endocrine tumours: role of MDCT and MRI

PURPOSE

This study was done to compare the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative assessment of nonfunctioning pancreatic endocrine tumours (NFPET).

MATERIALS AND METHODS

Fifty-one patients (25 men, 26 women; mean age, 52 years), preoperatively investigated by both MDCT and MRI and subsequently operated on with a histological diagnosis of NFPET, were included in this study. MDCT and MRI accuracy in evaluating location, size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, infiltration of peritumoural vessels, involvement of locoregional lymph nodes, and liver metastases was compared using Pearson correlation, Mann-Whitney and chi-square tests. A value of p<0.05 was considered statistically significant.

RESULTS

MDCT and MRI had similar accuracy in assessing size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, involvement of locoregional lymph nodes, and liver metastases (p>0.05). MDCT was superior to MRI in evaluating the infiltration of peritumoural vessels (p=0.025).

CONCLUSIONS

MDCT performed better than MRI in assessing vascular involvement and should be considered the best imaging tool for preoperative evaluation of NFPET.

Comparison of WHO Classifications (2004, 2010), the Hochwald grading system, and AJCC and ENETS staging systems in predicting prognosis in locoregional well-differentiated pancreatic neuroendocrine tumors

It is difficult to predict prognosis in patients with locoregional well-differentiated (WD) pancreatic neuroendocrine tumors (PanNET). We aimed to examine commonly used stratification systems [World Health organization (WHO) 2004 and 2010 classifications, American Joint Committee on Cancer (AJCC) and European Neuroendocrine Tumor Society (ENETS) staging, and the Hochwald grading system] for their power in predicting recurrence-free survival (RFS) in these patients. Seventy-five such patients (mean age 56 y, mean follow-up 79 mo) who underwent resection with sufficient tissue material and follow-up data were studied. RFS was correlated with variable clinicopathologic features and stratified with above-mentioned systems. Concordance index (CI) was then calculated. With the WHO 2004 classification, 16, 35, and 24 PanNETs were classified as benign behavior, uncertain behavior, and WD endocrine carcinoma, respectively. By the WHO 2010 classification, 26, 41, and 8 tumors were grade 1, 2, and 3, respectively. Using the Hochwald system, 47 were low grade, and 28 were intermediate grade. The AJCC staging information was complete for 62 patients (13 had the lymph node status Nx) and included: stages IA (19/62), IB (10/62), IIA (10/62), and IIB (23/62). The ENETS staging information was stages I (16/62), IIa (8/62), IIb (14/62), IIIa (0/62), and IIIb (24/62). The average Ki-67 proliferation index (PI) was 8.1%. Factors that predicted RFS included tumor size, nodal metastasis, vascular invasion, perineural invasion, necrosis, mitosis, and Ki-67 PI (all P<0.01). The CI for each system was: 0.6361 for WHO 2004, 0.6735 for WHO 2010, 0.6495 for AJCC staging, 0.6642 for ENETS staging, and 0.6851 for the Hochwald grading system. When these systems were analyzed in conjunction with various additional important pathologic features, combination of the Hochwald grading system and Ki-67 PI achieved the highest CI (0.7946). Therefore, although all these systems predict RFS well in locoregional WD PanNETs, the Hochwald grading system achieves the highest predictive ability. Further predictive power can be achieved by combining the Hochwald grading system and Ki-67 PI.

Ki-67 is a reliable pathological grading marker for neuroendocrine tumors

In neuroendocrine tumors (NETs), proliferation markers, especially Ki-67, have become increasingly important. This study was designed to examine the reproducibility of Ki-67 for use in the current classification of NETs. A retrospectively assembled integrated database with prospectively collected data of patients undergoing multidisciplinary management for NETs from 2000 to 2009 was analyzed. Original pathology was reviewed to reassess Ki-67 values. Ki-67 was then categorized to grades G1 (≤2 %), G2 (3-20 %), or G3 (>20 %) according to the European Neuroendocrine Tumor Society (ENETS) guidelines and the 2010 World Health Organization (WHO) classification. Original Ki-67 values were compared to reviewed values. All statistical analyses were carried out using SAS 9.1.3. A total of 184 patients were included of which 48 % were male. The most common primary NET site was the small bowel, in 27 %. On pathology review, there was 94 % agreement for G1, with 4 % of cases upgraded at review to G2 and 2 % of cases upgraded to G3. For G2, there was 94 % agreement, with 6 % of cases downgraded to G1 and 0 % upgraded. For G3, there was 90 % agreement, with 10 % of cases downgraded to G2 and none to G1 (kappa = 0.89). Ki-67 is a proliferative marker for NETs that is highly reproducible when used to grade tumors according to ENETS and WHO categories. The high inter-institutional reliability in the determination of tumor grade as assessed by Ki-67 makes it a reliable tool in the assessment of patients with NETs.

Pathology reporting of neuroendocrine tumors: essential elements for accurate diagnosis, classification, and staging

Much recent debate has focused on the optimal classification of epithelial neuroendocrine tumors (NETs). Multiple different systems of terminology, grading, and staging have been proposed, and some systems combine elements of grade and stage into a single prognostic classification. Recently, national and international consensus groups have attempted to standardize the classification of NETs, especially for those arising in the gastrointestinal tract and pancreas. Furthermore, the recognition that common classification criteria (such as proliferative rate) span multiple different systems allows the basic data necessary to predict outcome and tailor therapy to be included in pathology reports, even though a single uniform system of terminology may remain elusive. Formal tumor-node-metastasis (TNM)-based staging systems also have been developed recently, and advances in the treatment of some NETs (pancreatic in particular) are pointing towards the need to assess therapeutic biomarkers in routine practice. This review will present the most widely used systems for classifying, grading, and staging NETs and will summarize the recommendations for the data to be included in standard pathology reports of these uncommon tumors.

A comparison of Ki-67 and mitotic count as prognostic markers for metastatic pancreatic and midgut neuroendocrine neoplasms

Background:

The aim of this study was to compare mitotic count (MC) and Ki-67 proliferation index as prognostic markers in pancreatic and midgut neuroendocrine neoplasms (NENs).

Methods:

Two hundred eighty-five patients with metastatic NENs were recruited. Concordance between histological grade according to either Ki-67 or MC as defined by the European Neuroendocrine Tumour Society guidelines was assessed and the prognostic significance of Ki-67 or MC were evaluated.

Results:

There was a discrepancy of 44 and 38% in grade assignment when using Ki-67 or MC in pancreatic and midgut NENs, respectively. In multivariate analysis, grade using Ki-67, but not MC, was a significant prognostic factor in determining overall survival (hazard ratios: midgut G2 2.34, G3 15.1, pancreas G2 2.08, G3 11.3). The prognostic value of Ki-67 was improved using a modified classification (hazard ratios: midgut G2 3.02, for G3 22.1, pancreas G2 5.97, G3 33.8).

Conclusion:

There is a lack of concordance between Ki-67 and MC in assigning tumour grade. Grade according to Ki-67 was a better prognostic marker than MC for metastatic pancreatic and midgut NENs. We suggest that Ki-67 alone should be used for grading pancreatic and midgut NENs and that the current threshold for classifying G1/G2 tumours should be revised from 2 to 5%.

Intervention in gastro-enteropancreatic neuroendocrine tumours

Neuroendocrine tumours require dedicated interventions to control their capacity to secrete hormones but also, antitumour growth strategies. Recommendations for early interventions in NET include the management of hormone-related symptoms and poorly differentiated neuroendocrine carcinomas. In contrast, prognostic heterogeneity is a key feature of well differentiated NET that complexified the antitumour strategy whatever the stage in this subgroup of tumour. In this review, timely therapeutic interventions to control hormone-related symptoms and tumour growth in GEP NET patients are discussed. The necessity of controlling hormone-related symptoms as the first step of any strategy affects also the tumour growth control strategy. In the absence of cure at the metastatic stage, progresses are expected in the recognition of well differentiated NET subgroups that display either excellent or poor prognosis.

Pathology - grading and staging of GEP-NETs

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) constitute a heterogeneous group of neoplasms. In the last few decades, due to a substantial rise in incidence and prevalence, GEP-NETs have been included among the most common tumours of the gastrointestinal tract. Diagnosis could be challenging and a significant number of patients present with metastatic or unresectable disease. The development of appropriate tools for standardised prognostic stratification and the introduction of effective target therapies have opened new horizons for planning tailored surgical or medical management and follow-up programs for these complex neoplasms. An overview on the GEP-NETs' diagnostic and prognostic criteria proposed by the recently published WHO classification and ENETS and UICC TNM staging systems is presented, focussing on their impact on the clinical and therapeutical approaches.

Prognostic relevance of survivin in pancreatic endocrine tumors

BACKGROUND

Better prognostic markers are needed for pancreatic endocrine tumors. Survivin is an apoptosis inhibitor that is suggested to have a negative prognostic impact in several tumor types. Contradictory data exist, especially regarding the significance of a nuclear versus cytoplasmic location of survivin. The prognostic relevance of nuclear and cytoplasmic survivin expression in pancreatic endocrine tumors-controlled for the tumor Ki-67 index, World Health Organization classification, and TNM stage-was investigated.

METHODS

A total of 111 patients treated at a tertiary referral center were retrospectively evaluated. Clinical data were gathered from medical records. Immunohistochemistry for survivin and Ki-67 was performed on paraffin-embedded tissue. Univariate and multivariate Cox analyses were performed.

RESULTS

Patients with tumors that had <5% survivin-positive nuclei had a mean survival of 225 months [95% confidence interval (CI) 168-281]. The corresponding figure for patients with 5 to 50% survivin-positive tumor cell nuclei was 101 months [95% CI 61-140; hazard ratio (HR) 2.4; P < 0.01) and with >50% survivin-positive nuclei 47 months (95% CI 24-71; HR 4.9; P < 0.001). Nuclear survivin expression in >50% of the tumor cells was an independent marker of a poor prognosis (HR 5.7; P < 0.01). Cytoplasmic survivin was not a significant prognostic factor in the multivariate analysis (HR 0.94; P = 0.90).

CONCLUSIONS

High expression of nuclear survivin is a significant marker of a poor prognosis in patients with a pancreatic endocrine tumor.

Succinate dehydrogenase B subunit immunohistochemical expression predicts aggressiveness in well differentiated neuroendocrine tumors of the ileum

Immunohistochemical loss of the succinate dehydrogenase subunit B (SDHB) has recently been reported as a surrogate biomarker of malignancy in sporadic and familial pheocromocytomas and paragangliomas through the activation of hypoxia pathways. However, data on the prevalence and the clinical implications of SDHB immunoreactivity in ileal neuroendocrine tumors are still lacking. Thirty-one consecutive, advanced primary midgut neuroendocrine tumors and related lymph node or liver metastases from 24 males and seven females were immunohistochemically assessed for SDHB. All patients were G1 tumors (Ki-67 labeling index ≤2%). SDHB immunohistochemistry results were expressed as immunostaining intensity and scored as low or strong according to the internal control represented by normal intestinal cells. Strong positivity for SDHB, with granular cytoplasmatic reactivity, was found in 77% of primary tumors (T), whilst low SDHB expression was detected in 90% of metastases (M). The combined analysis (T+M) confirmed the loss of SDHB expression in 82% of metastases compared to 18% of primary tumors. SDHB expression was inversely correlated with Ki-67 labeling index, which accounted for 1.54% in metastastic sites and 0.7% in primary tumors. A correlation between SDHB expression loss, increased Ki-67 labeling index and biological aggressiveness was shown in advanced midgut neuroendocrine tumors, suggesting a role of tumor suppressor gene.

Ki-67 predicts disease recurrence and poor prognosis in pancreatic neuroendocrine neoplasms

BACKGROUND

Pancreatic neuroendocrine neoplasms are rare malignancies for which the ideal staging method remains controversial. Ki-67 is a cell proliferation marker that has been shown to have some utility in predicting prognosis in neuroendocrine neoplasms. We sought to test the predictive ability of Ki-67 staining for disease recurrence and overall survival (OS) in pancreatic neuroendocrine neoplasms.

METHODS

The medical records of patients who underwent pancreatic resection for pancreatic neuroendocrine neoplasms at a tertiary referral hospital from 1994 to 2009 were reviewed. The pathologic specimens of all were stained for Ki-67 and recorded as percentage of cells staining positive per high-powered field. The 10-year disease-free and OSs were analyzed.

RESULTS

We identified 140 patients. Gender and age were not associated with increased risk of disease recurrence. Patients with tumors >4 cm or with Ki-67 staining >9% were more likely to have disease recurrence (P = .0454 and .047) and have decreased OS (P < .0001 and .0007).

CONCLUSION

Increasing tumor size and increasing Ki-67 staining both correlate with increased risk of disease recurrence and decreased OS. Designing a staging system that incorporates both of these clinical variables will enable better identification of patients at risk for recurrent pancreatic neuroendocrine neoplasms.

Comparison of methods for proliferative index analysis for grading pancreatic well-differentiated neuroendocrine tumors

Assessment of proliferative activity is required for grading well-differentiated pancreatic neuroendocrine tumors. However, a standardized method for obtaining the Ki-67 proliferative index is lacking. This study compared proliferative activity obtained by 3 methods: single-field hot spot (Ki-67 HS) and 10 consecutive field average (Ki-67 CFA) using the Ventana image analysis system (Ventana Medical Systems, Tucson, AZ) and mitotic index (MI). These methods resulted in discrepant grades in 30 (67%) of our 45 cases. With the current Ki-67 cutoff of more than 2% for intermediate-grade tumors, MI, CFA, and HS resulted in specificities of 91%, 94%, and 31%, respectively, for detecting metastasis, with positive predictive values (PPVs) of 25%, 67%, and 31%, respectively. At a higher Ki-67 cutoff of 7.5%, HS analysis resulted in a specificity of 94% and PPV of 71% for predicting metastasis. While single-field HS analysis may be practical and reliable at a higher cutoff, this study emphasizes the variability that can exist when different methods of assessment are used.

Risk factors for disease progression in advanced jejunoileal neuroendocrine tumors

BACKGROUND

Knowledge of clinical course in advanced jejunoileal neuroendocrine tumors (NETs) is poor.

AIM

To investigate progression-free survival (PFS), overall survival (OS), and possible predictors for disease progression (DP) in advanced jejunoileal NETs.

PATIENTS AND METHODS

We carried out a multicenter, retrospective analysis of incoming patients with sporadic advanced jejunoileal NETs. PFS and OS were assessed by Kaplan-Meier analysis. Risk factors for progression were analyzed by the Cox proportional hazards method.

RESULTS

Of the 114 patients enrolled, 46.5% had functioning tumors, 93.9% had stage IV disease, and 57.3 and 42.7% were G1 and G2 tumors, respectively. During a median follow-up of 48 months (interquartile range 29-84 months), DP occurred in 61.4% of patients, after 19 months (interquartile range 10-41 months) from diagnosis. Median PFS was 36 months. The 2-year and 5-year PFS were 59 and 33%, respectively, while 5-year OS was 77.5%. Ki67 was the sole strong independent risk factor for unfavorable outcome according to multivariate analysis, being significantly associated with both PFS and OS.

CONCLUSIONS

DP occurred in the majority of patients with advanced jejunoileal NETs, with median PFS being 36 months. Ki67 was a significant predictor of DP and should be considered in determining appropriate treatments and planning follow-up for these patients.

Survival impact of malignant pancreatic neuroendocrine and islet cell neoplasm phenotypes

BACKGROUND

The low incidence of malignant "functional" (F) or "nonfunctional" (NF) neuroendocrine islet cell tumors (ICTs) of the pancreas represents a challenge to precise post-therapeutic survival prediction. This study examined the survival impact of malignant pancreatic ICT morphologic subtypes.

METHODS

A pancreatic ICT data set was created from a US-based population database from 1980-2004. Prognostic factors with survival impact and relationships between surgical therapy and overall survival (OS) were analyzed.

RESULTS

There were 2,350 individuals with malignant ICTs. Histologic subtypes included carcinoid tumors, islet cell carcinomas, neuroendocrine carcinomas, and malignant gastrinomas, insulinomas, glucagonomas, or VIPomas. There was no difference in resection rates between FICTs and NFICTs (23% vs. 20%, P = ns). Median OS was 30 months, with group differences ranging from NE carcinomas (21) to VIPomas (96; P < 0.0001). Median OS of resected versus unresected FICTs was 172 versus 37 months, while that of NFICTs was 113 versus 18 months (P < 0.0001). Compared to neuroendocrine carcinomas, hazard ratios were: VIPomas 0.48, gastrinomas 0.65, carcinoid tumors 0.76, insulinomas 0.84, glucagonomas 0.93, and islet cell carcinomas 1.0.

CONCLUSIONS

When controlled for other established prognostic parameters, histopathologic subtype assignment of pancreatic ICTs affects survival prediction. Resection is associated with superior survival for all tumor types.

Metastatic and locally advanced pancreatic endocrine carcinomas: analysis of factors associated with disease progression

PURPOSE

Knowledge of clinical course of pancreatic endocrine carcinomas (PECs) is poor. This study aimed to determine the time to progression of advanced PECs, and to identify predictors capable of selecting subgroups with higher risk of progression.

PATIENTS AND METHODS

In this multicenter retrospective analysis, patients with advanced PECs were enrolled. Staging was according to European Neuroendocrine Tumors Society guidelines. Grading was based on proliferation index using Ki67 immunohistochemistry. The primary end point was progression-free survival (PFS), which was assessed using the Kaplan-Meier method. The Cox regression proportional hazard model was used to identify predictors for tumor progression.

RESULTS

Two hundred two patients with PECs were enrolled, including 172 with well-differentiated and 30 with poorly differentiated endocrine carcinomas. There were 34 patients with stage III and 168 with stage IV tumors. G1 tumors were present in 19.7% of patients, whereas 60.1% of patients had G2 tumors, and the remaining 20.2% had G3 tumors. Disease progression occurred in 166 patients (82.2%), at a median interval of 10 months (interquartile range, 5 to 22) from diagnosis. Median PFS was 14 months. Different PFS were observed depending on G grade (P < .001) and tumor differentiation (P < .001) and in patients who did not receive any antitumor treatment (P = .002). The major risk factor for progression was the proliferation index Ki67 (hazard ratio, 1.02 for each increasing unit; P < .001). Overall 5-year survival was 44.1%.

CONCLUSION

The vast majority of patients with advanced PECs undergo disease progression. The major risk factor for progression is Ki67 index, which should lead physicians dealing with PECs to plan appropriate follow-up programs and therapeutic strategies.

Neuroendocrine tumors of midgut and hindgut origin: tumor-node-metastasis classification determines clinical outcome

BACKGROUND

Prognostic classification of neuroendocrine tumor (NET) patients is difficult due to the complexity of current classification systems. A recent proposal for a tumor-node-metastasis (TNM) classification and a grading system based on the proliferative fraction proved valid in NETs of foregut origin. The purpose of this study was to test the efficacy of a proposal for TNM staging and grading for midgut and hindgut NETs.

METHODS

Two hundred seventy patients with histologically proven midgut and hindgut NETs were investigated. Epidemiological, clinicopathological, and tumor-specific data at initial diagnosis were recorded. Tumors were classified according to the World Health Organization (WHO) and the recent European Neuroendocrine Tumor Society-TNM staging and grading proposal. Survival analysis and statistical testing for independent prognostic factors were performed using log-rank tests and Cox regression.

RESULTS

Of 270 NETs originating in the midgut or hindgut, 7% (5-year survival rate [YSR], 100%) were stage 1, 8% (5-YSR, 100%) were stage 2, 19% (5-YSR, 89.5%) were stage 3, and 66% (5-YSR, 83.3%) were stage 4 NETs; 62% (5-YSR 95.2%) were grade 1, 32% (5-YSR 82.0%) were grade 2, and 6% (5-YSR, 51.4%) were grade 3 NETs. WHO classification significantly separated poorly from well-differentiated NET or carcinomas but did not further discriminate. TNM staging significantly separated stages 1, 2, and 3 from stage 4 NETs, as did grading according to proliferative capacity for all grades. Multivariate analysis confirmed these results, particularly for Ki67 grading.

CONCLUSIONS

The acquired data confirmed the prognostic relevance of the proposed TNM staging and grading system and demonstrated the applicability of these classification tools. The TNM system can therefore facilitate therapeutic stratification and comparison of data from different institutions.