The deubiquitinase USP9X suppresses pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) remains a lethal malignancy despite tremendous progress in its molecular characterization. Indeed, PDA tumors harbor four signature somatic mutations^1–4, and a plethora of lower frequency genetic events of uncertain significance⁵. Here, we used Sleeping Beauty (SB) transposon-mediated insertional mutagenesis^6,7 in a mouse model of pancreatic ductal preneoplasia⁸ to identify genes that cooperate with oncogenic Kras^G12D to accelerate tumorigenesis and promote progression. Our screen revealed new candidates and confirmed the importance of many genes and pathways previously implicated in human PDA. Interestingly, the most commonly mutated gene was the X-linked deubiquitinase Usp9x, which was inactivated in over 50% of the tumors. Although prior work had attributed a pro-survival role to USP9X in human neoplasia⁹, we found instead that loss of Usp9x enhances transformation and protects pancreatic cancer cells from anoikis. Clinically, low USP9X protein and mRNA expression in PDA correlates with poor survival following surgery, and USP9X levels are inversely associated with metastatic burden in advanced disease. Furthermore, chromatin modulation with trichostatin A or 5-aza-2′-deoxycytidine elevates USP9X expression in human PDA cell lines to suggest a clinical approach for certain patients. The conditional deletion of Usp9x cooperated with Kras^G12D to rapidly accelerate pancreatic tumorigenesis in mice, validating their genetic interaction. Therefore, we propose USP9X as a major new tumor suppressor gene with prognostic and therapeutic relevance in PDA.

The prognostic and predictive value of serum CA19.9 in pancreatic cancer

Background

Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 (CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used.

Methods

We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC.

Results

By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P = 0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels >90 U/ml did not benefit from adjuvant chemotherapy (P = 0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P = 0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P = 0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%.

Conclusions

Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.

Clinicopathologic factors associated with HER2-positive gastric cancer and its impact on survival outcomes--a systematic review

With the availability of a therapeutic target and an effective agent in trastuzumab, a systematic examination of the literature to investigate the role of human epidermal growth factor 2 (HER2) as a prognostic factor for survival and its association with clinicopathologic markers may improve treatment. An electronic search of the MEDLINE and PubMed databases (January 1990 to January 2011) was undertaken to identify translational studies that correlated HER2 with clinicopathologic markers and/or survival outcome. This review included 49 studies totaling 11,337 patients. Forty-four percent of patients had Stage I/II, and 56% had Stage III/IV disease. Immunohistochemistry was most commonly used to assess HER2 expression, identifying a median rate of 18% (range, 4-53%) of gastric cancer demonstrating HER2 overexpression. In patients with and without HER2 overexpression, the median 3-year disease-free survival rate was 58% (range, 50-88%) and 86% (range, 62-97%), respectively. Of the 35 studies reporting the impact of HER2 overexpression on survival, 20 studies (57%) reported no difference in overall survival, two studies (6%) reported significantly longer overall survival in patients with HER2 overexpression and 13 studies (37%) reported significantly poorer overall survival in patients with HER2 overexpression. The median overall survival and 5-year survival rate was 21 (range, 10-57) months and 42%, and 33 (range, 13-80) months and 52% in patients with and without HER2 overexpression, respectively. HER2 overexpression appears to be associated with poorer survival and with intestinal-type gastric cancer in this group of patients for whom majority undergone curative gastrectomy.

Clinical and immunohistochemical features of 34 solid pseudopapillary tumors of the pancreas

BACKGROUND AND AIM

Clinicopathological data regarding pancreatic solid pseudopapillary tumors (SPT) in a multiethnic country are limited. The aim of the present study was to characterize pancreatic SPT in Australia.

METHODS

Clinicopathological features, treatment, immunohistochemical findings and outcome data of 34 patients (79% Caucasian, 12% Asian, 6% South Pacific Islander and 3% African) with pancreatic SPT were reviewed.

RESULTS

The most presenting complaint was abdominal pain. Median diameter of tumors was 60 mm (range: 20-220); predominantly located in the pancreatic tail (tail : body : head = 23:3:8). All tumors were resected and patients underwent surgery, including a liver resection for metastasis, all patients were alive after a median follow up of 70 months (IQR: 48-178). Two patients underwent repeated surgery for local recurrences with liver metastases after 8 and 18 months, which were successfully managed by surgical resection. Completeness of excision, perineural spread, vascular space invasion, mitotic rate and cellular atypia did not predict recurrence. In all cases, there was aberrant nuclear staining of beta-catenin and a loss of membranous expression of E-cadherin with aberrant nuclear localization of the cytoplasmic domain. Most pancreatic SPT were also strongly positive for CD10 (96%), progesterone receptor (79%), cytokeratin (28%), synapthophysin (26%) and chromogranin (15%).

CONCLUSIONS

Pancreatic SPT occur in all races and are uniformly indolent. Given complete resection of a pancreatic SPT is usually curative and recurrences can be treated with re-operation, correct diagnosis is important.

Expression of S100A2 calcium-binding protein predicts response to pancreatectomy for pancreatic cancer

BACKGROUND & AIMS

Current methods of preoperative staging and predicting outcome following pancreatectomy for pancreatic cancer (PC) are inadequate. We evaluated the utility of multiple biomarkers from distinct biologic pathways as potential predictive markers of response to pancreatectomy and patient survival.

METHODS

We assessed the relationship of candidate biomarkers known, or suspected, to be aberrantly expressed in PC, with disease-specific survival and response to therapy in a cohort of 601 patients.

RESULTS

Of the 17 candidate biomarkers examined, only elevated expression of S100A2 was an independent predictor of survival in both the training (n = 162) and validation sets (n = 439; hazard ratio [HR], 2.19; 95% confidence interval [CI]: 1.48-3.25; P < .0001) when assessed in a multivariate model with clinical variables. Patients with high S100A2 expressing tumors had no survival benefit with pancreatectomy compared with those with locally advanced disease, whereas those without high S100A2 expression had a survival advantage of 10.6 months (19.4 vs 8.8 months, respectively) and a HR of 3.23 (95% CI: 2.39-4.33; P < .0001). Of significance, patients with S100A2-negative tumors had a significant survival benefit from pancreatectomy even in the presence of involved surgical margins (median, 15.7 months; P = .0007) or lymph node metastases (median, 17.4 months; P = .0002).

CONCLUSIONS

S100A2 expression is a good predictor of response to pancreatectomy for PC and suggests that high S100A2 expression may be a marker of a metastatic phenotype. Prospective measurement of S100A2 expression in diagnostic biopsy samples has potential clinical utility as a predictive marker of response to pancreatectomy and other therapies that target locoregional disease.

Surgical therapy for gastrointestinal stromal tumours of the upper gastrointestinal tract

AIM

This study aimed to examine clinicopathological features and outcomes after primary resection of gastrointestinal stromal tumours (GIST) of the upper gastrointestinal tract

METHOD

Fifty consecutive patients were identified as having a mesenchymal tumour of the upper gastrointestinal tract resected at our institution, of which 47 were GISTs. The influence of clinicopathological variables on disease-free survival was evaluated using Kaplan-Meier estimates and Cox hazard model.

RESULTS

The median age was 62.8 (21.3-94.7). The commonest presenting symptoms were anaemia (43%) and pain (34%). Tumours were located in the stomach (64%), small bowel (34%) and oesophagus (2%). Median follow-up was 20.4 (2-106) months. Fletcher low/intermediate-risk tumours had a significantly better (p = 0.0008) 2- and 5-year actuarial survival of 100% compared with 88% and 58% for high-risk group. Recurrence-free survival at 2 and 5 years was 100% for low/intermediate-risk group compared with 68% and 45% for the high-risk group (p = 0.0008). Univariate analysis of predictors of recurrence identified male sex, high mitotic rate and tumour size as significant. Multivariate analysis showed high mitotic rate as the only poor prognosticator (Hazard ratio = 16.7, p = 0.02).

CONCLUSION

Surgical excision of low- and intermediate-grade GIST has an excellent prognosis. Surgery remains the mainstay of treatments, and high-grade tumours carry a significantly worse prognosis. High mitotic rates are an independent poor prognosticator.

Margin clearance and outcome in resected pancreatic cancer

PURPOSE

Current adjuvant therapies for pancreatic cancer (PC) are inconsistently used and only modestly effective. Because a high proportion of patients who undergo resection for PC likely harbor occult metastatic disease, any adjuvant trials assessing therapies such as radiotherapy directed at locoregional disease are significantly underpowered. Stratification based on the probability (and volume) of residual locoregional disease could play an important role in the design of future clinical trials assessing adjuvant radiotherapy.

PATIENTS AND METHODS

We assessed the relationships between margin involvement, the proximity to operative resection margins and outcome in a cohort of 365 patients who underwent operative resection for PC.

RESULTS

Microscopic involvement of a resection margin by tumor was associated with a poor prognosis. Stratifying the minimum clearance of resection margins by 0.5-mm increments demonstrated that although median survival was no different to clear margins based on these definitions, it was not until the resection margin was clear by more than 1.5 mm that optimal long-term survival was achieved.

CONCLUSION

These data demonstrate that a margin clearance of more than 1.5 mm is important for long-term survival in a subgroup of patients. More aggressive therapeutic approaches that target locoregional disease such as radiotherapy may be beneficial in patients with close surgical margins. Stratification of patients for entry onto future clinical trials based on this criterion may identify those patients who benefit from adjuvant radiotherapy.

Role of endoscopic ultrasound in pancreatic cancer

Pancreatic cancer (PC) is the fourth most common cause of cancer deaths in Western societies. It is an aggressive tumor with an overall 5-year survival rate of less than 5%. Surgical resection offers the only possibility of cure and long-term survival for patients suffering from PC; however, unfortunately, fewer than 20% of patients suffering from PC have disease that is amendable to surgical resection. Therefore, it is important to accurately diagnose and stage these patients to enable optimal treatment of their disease. The imaging modalities involved in the diagnosis and staging of PC include multidetector CT scanning, endoscopic ultrasound (EUS), endoscopic retrograde cholangiopancreaticography and MRI. The roles and relative importance of these imaging modalities have changed over the last few decades and continue to change owing to the rapid technological advances in medical imaging, but these investigations continue to be complementary. EUS was first introduced in the mid-1980s in Japan and Germany and has quickly gained acceptance. Its widespread use in the last decade has revolutionized the management of pancreatic disease as it simultaneously provides primary diagnostic and staging information, as well as enabling tissue biopsy. This article discusses the potential benefits and drawbacks of EUS in the primary diagnosis, staging and assessment of resectability, and EUS-guided fine-needle aspiration in PC. Difficult diagnostic scenarios and pitfalls are also discussed. A suggested management algorithm for patients with suspected PC is also presented.

Synoptic reporting improves histopathological assessment of pancreatic resection specimens

AIM

We examined whether introduction of a standardised pancreatic cancer minimum data set improved the reporting of key pathological features across multiple institutions.

METHODS

From seven different pathology departments that are members of the New South Wales Pancreatic Cancer Network, 109 free text reports and 68 synoptic reports were compared.

RESULTS

AJCC stage could not be inferred from 44% of free text reports, whereas stage was reported in all 68 synoptic reports. In the free text reports 28 different names were used to designate margins. All margins were reported in only 12 (11%) of the free text reports compared with 64 (94%) of the synoptic reports (p = 0.0011). The presence or absence of lymphovascular or perineural invasion was reported in 72 (66%) and 92 (84%) of free text reports, respectively. In contrast, lymphovascular space and perineural invasion were reported in all synoptic reports (p = 0.0011 and p = 0.0058).

CONCLUSION

We conclude that synoptic reporting of pancreatic resections without any other intervention increases the information contained within histopathology reports. Therefore, the introduction of minimal data set synoptic reports is a simple and feasible mechanism to immediately improve reporting for pancreatectomy specimens.

Superior mesenteric artery syndrome: diagnosis and treatment strategies

INTRODUCTION

Superior mesenteric artery (SMA) syndrome is an unusual cause of vomiting and weight loss resulting from the compression of the third part of the duodenum by the SMA. Various medical and psychiatric conditions may result in the initial rapid weight loss which causes narrowing of the aortomesenteric angle. The vomiting and obstructive syndrome is then self-perpetuated regardless of the initiating factors. The young age and nonspecific symptoms often lead to a delay in diagnosis.

DISCUSSION

A series of eight cases is presented reviewing the presentation, investigations, surgical treatment by division of duodenum and duodenojejunostomy, and outcomes.

CONCLUSION

SMA syndrome is a well-described entity which must be considered as a cause of vomiting associated with significant weight loss in young adults. Surgical treatment should be allied with psychological assessment to treat any underlying psychosocial abnormality.

In vivo confocal endomicroscopy in the diagnosis and evaluation of celiac disease

BACKGROUND & AIMS

Accurate histopathology of endoscopic duodenal biopsy specimens is critical in the diagnosis of celiac disease (CD) but sampling error and poor quality specimens may generate a false-negative result. Confocal endomicroscopy (CEM) is a novel technology allowing real-time in vivo microscopy of the mucosa that may diagnose CD and evaluate its severity and response to treatment more accurately than histopathology.

METHODS

Subjects with CD and controls prospectively underwent CEM. Features of villous atrophy and crypt hypertrophy were defined. A CEM score measuring CD severity was devised and validated against the diagnosis of CD and blinded histopathology. Receiver operator characteristics, sensitivity to change after treatment, and reliability of findings were assessed.

RESULTS

From 31 patients (6 untreated CD, 11 treated CD, and 14 controls), 7019 CEM images paired with 326 biopsy specimens were obtained. The accuracy of CEM in diagnosing CD was excellent (receiver operator characteristics area under the curve, 0.946; sensitivity, 94%, specificity, 92%) and correlated well with the Marsh grading (R-squared, 0.756). CEM differentiated CD from controls (P < .0001) and was sensitive to change after treatment with gluten-free diet (1787 optical biopsies; P = .012). The intraclass correlation of reliability was high (0.759-0.916). Of the 17 cases with diagnosed CD, 16 (94%) were diagnosed correctly using CEM but only 13 (76%) had detectable histopathology changes. The procedure was safe and well-tolerated.

CONCLUSIONS

CEM effectively diagnoses and evaluates CD severity in vivo. This promising technique has the potential to improve endoscopy efficiency.

Improving outcomes for operable pancreatic cancer: is access to safer surgery the problem?

Despite advances in the understanding and treatment of pancreatic cancer in the last two decades, there is a persisting nihilistic attitude among clinicians. An alarmingly high rate of under-utilization of surgical management for operable pancreatic cancer was recently reported in the USA, where more than half of patients with stage 1 operable disease and no other contraindications were not offered surgery as therapy, denying this group of patients a 20% chance of long-term survival. These data indicate that a nihilistic attitude among clinicians may be a significant and reversible cause of the persisting high mortality of patients with pancreatic cancer. This article examines the modern management of pancreatic cancer, in particular, the advances in surgical care that have reduced the mortality of pancreatectomy to almost that of colonic resection, and outlines a strategy for improving outcomes for patients with pancreatic cancer now and in the future.

A novel approach to high definition, high-contrast video capture in abdominal surgery

OBJECTIVE

The aim of this study was to define the best available option for video capture of surgical procedures for educational and archival purposes, with a view to identifying methods of capturing high-quality footage and identifying common pitfalls.

SUMMARY BACKGROUND DATA

Several options exist for those who wish to record operative surgical techniques on video. While high-end equipment is an unnecessary expense for most surgical units, several techniques are readily available that do not require industrial-grade audiovisual recording facilities, but not all are suited to every surgical application.

METHODS

We surveyed and evaluated the available technology for video capture in surgery. Our evaluation included analyses of video resolution, depth of field, contrast, exposure, image stability, and frame composition, as well as considerations of cost, accessibility, utility, feasibility, and economies of scale.

RESULTS

Several video capture options were identified, and the strengths and shortcomings of each were catalogued. None of the commercially available options was deemed suitable for high-quality video capture of abdominal surgical procedures. A novel application of off-the-shelf technology was devised to address these issues.

CONCLUSIONS

Excellent quality video capture of surgical procedures within deep body cavities is feasible using commonly available equipment and technology, with minimal technical difficulty.

Drainage of hepatic hydatid cyst with a surgiport

This article describes the safe and effective technique of hepatic hydatid cyst drainage.

Serum elastase in the diagnosis of acute pancreatitis: a prospective study

BACKGROUND

The aim of the present study was to evaluate the usefulness of the elastase 1 (E1) enzyme-linked immunosorbent assay (ELISA) in the diagnosis of acute pancreatitis. This is the first Australian evaluation of the E1 ELISA.

METHODS

Three groups of patients were prospectively assessed: control patients, patients with acute pancreatitis, and patients with acute non-pancreatitic abdominal pain. Serum was collected on all patients on admission and the sensitivity, specificity and diagnostic accuracy of serum elastase, amylase and lipase was determined.

RESULTS

Twenty-nine patients with 30 episodes of pancreatitis, 38 patients with acute non-pancreatitic abdominal pain and 121 control patients were studied. For all patient episodes E1 ELISA at a cut-off of 3.5 ng/mL had a sensitivity of 80%, specificity of 96% and an efficiency of 94% in the diagnosis of acute pancreatitis. For episodes more than 48 h after onset of symptoms, sensitivity was 100%, specificity was 96% and diagnostic efficiency was 96%. This performance was equivalent to amylase but inferior to lipase.

CONCLUSION

Of the biochemical markers for pancreatitis currently available, lipase is the most useful. The relatively inferior sensitivity and problematic reference range for the ELISA E1, together with its limitations in measuring total elastase, currently prevent its widespread use.

Desmoplastic reaction in pancreatic cancer: role of pancreatic stellate cells

OBJECTIVES

Pancreatic cancer has a very poor prognosis, largely due to its propensity for early local and distant spread. Histopathologically, most pancreatic cancers are characterized by a prominent stromal/fibrous reaction in and around tumor tissue. The aims of this study were to determine whether (1) the cells responsible for the formation of the stromal reaction in human pancreatic cancers are activated pancreatic stellate cells (PSCs) and (2) an interaction exists between pancreatic cancer cells and PSCs that may facilitate local and distant invasion of tumor.

METHODS

Serial sections of human pancreatic cancer tissue were stained for desmin and glial fibrillary acidic protein (stellate cell selective markers) and alpha-smooth muscle actin (alphaSMA), a marker of activated PSC activation, by immunohistochemistry, and for collagen using Sirius Red. Correlation between the extent of positive staining for collagen and alphaSMA was assessed by morphometry. The cellular source of collagen in stromal areas was identified using dual staining methodology, ie, immunostaining for alphaSMA and in situ hybridization for procollagen alpha1I mRNA. The possible interaction between pancreatic cancer cells and PSCs was assessed in vitro by exposing cultured rat PSCs to control medium or conditioned medium from 2 pancreatic cancer cell lines (PANC-1 and MiaPaCa-2) for 24 hours. PSC activation was assessed by cell proliferation and alphaSMA expression.

RESULTS

Stromal areas of human pancreatic cancer stained strongly positive for the stellate cell selective markers desmin and GFAP (indicating the presence of PSCs), for alphaSMA (suggesting that the PSCs were in their activated state) and for collagen. Morphometric analysis demonstrated a close correlation (r = 0.77; P < 0.04; 8 paired sections) between the extent of PSC activation and collagen deposition. Procollagen mRNA expression was localized to alphaSMA-positive cells in stromal areas indicating that activated PSCs were the predominant source of collagen in stromal areas. Exposure of PSCs to pancreatic cancer cell secretions in vitro resulted in PSC activation as indicated by significantly increased cell proliferation and alphaSMA expression.

CONCLUSIONS

Activated PSCs are present in the stromal reaction in pancreatic cancers and are responsible for the production of stromal collagen. PSC function is influenced by pancreatic cancer cells. Interactions between tumor cells and stromal cells (PSCs) may play an important role in the pathobiology of pancreatic cancer.