GEIS guidelines for gastrointestinal sarcomas (GIST)

Development of a Malignancy Potential Binary Prediction Model Based on Deep Learning for the Mitotic Count of Local Primary Gastrointestinal Stromal Tumors

Objective

The mitotic count of gastrointestinal stromal tumors (GIST) is closely associated with the risk of planting and metastasis. The purpose of this study was to develop a predictive model for the mitotic index of local primary GIST, based on deep learning algorithm.

Materials and Methods

Abdominal contrast-enhanced CT images of 148 pathologically confirmed GIST cases were retrospectively collected for the development of a deep learning classification algorithm. The areas of GIST masses on the CT images were retrospectively labelled by an experienced radiologist. The postoperative pathological mitotic count was considered as the gold standard (high mitotic count, > 5/50 high-power fields [HPFs]; low mitotic count, ≤ 5/50 HPFs). A binary classification model was trained on the basis of the VGG16 convolutional neural network, using the CT images with the training set (n = 108), validation set (n = 20), and the test set (n = 20). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at both, the image level and the patient level. The receiver operating characteristic curves were generated on the basis of the model prediction results and the area under curves (AUCs) were calculated. The risk categories of the tumors were predicted according to the Armed Forces Institute of Pathology criteria.

Results

At the image level, the classification prediction results of the mitotic counts in the test cohort were as follows: sensitivity 85.7% (95% confidence interval [CI]: 0.834–0.877), specificity 67.5% (95% CI: 0.636–0.712), PPV 82.1% (95% CI: 0.797–0.843), NPV 73.0% (95% CI: 0.691–0.766), and AUC 0.771 (95% CI: 0.750–0.791). At the patient level, the classification prediction results in the test cohort were as follows: sensitivity 90.0% (95% CI: 0.541–0.995), specificity 70.0% (95% CI: 0.354–0.919), PPV 75.0% (95% CI: 0.428–0.933), NPV 87.5% (95% CI: 0.467–0.993), and AUC 0.800 (95% CI: 0.563–0.943).

Conclusion

We developed and preliminarily verified the GIST mitotic count binary prediction model, based on the VGG convolutional neural network. The model displayed a good predictive performance.

Sarcomas: Immune biomarker expression and checkpoint inhibitor trials

Sarcomas are a heterogenous group of mesenchymal cancers comprising over 100 subtypes. Current chemotherapy for all but a very few subtypes has limited efficacy, resulting in 5-year relative survival rates of 16% for metastatic patients. While sarcomas have often been regarded as an "immune cold" tumor category, recent biomarker studies have confirmed a great deal of immune heterogeneity across sarcoma subtypes. Reports from the first generation of clinical trials treating sarcomas with immunotherapy demonstrate a few positive responses, supporting efforts to stratify patients to optimize response rates. This review summarizes recent advances in knowledge around immune biomarker expression in sarcomas, the potential use of new technologies to complement these study results, and clinical trials particularly of immune checkpoint inhibitor therapy in sarcomas. Each of the immune biomarkers assessed was reviewed for subtype-specific expression patterns and correlation with prognosis. Overall, there is extensive heterogeneity of immune biomarker presence across sarcoma subtypes, and no consensus on the prognostic effect of these biomarkers. New technologies such as multiplex immunohistochemistry and high plex in situ profiling may offer more insights into the sarcoma microenvironment. To date, clinical trials using immune checkpoint inhibitor monotherapy have not shown compelling clinical benefits. Combination therapy with dual checkpoint inhibitors or in combinations with other agents has yielded more promising results in dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma, angiosarcoma and alveolar soft-part sarcoma. Better understanding of the sarcoma immune status through biomarkers may help decipher the reasons behind differential responses to immunotherapy.

Neurofibromatosis type 1 associated multiple and cystic gastrointestinal tumors: 02 case reports

INTRODUCTION

GIST's are the most common mesenchymal tumor of the gastrointestinal tract, clinically and radiologically heterogeneous, only a histological study can confirm the diagnosis. The link between NF1 and GISTs have been established but not fully elucidated.

CASE PRESENTATION

we report 02 cases of NF1 associated GIST, a 60 years old woman with multiples GISTs in the duodenum, proximal jejunum and in the colon presenting an iron deficiency anemia due to chronic bleeding, operated with R0 resection and a low risk of recurrences and a 41 year old male patient with acute abdominal pain with a giant abdominal mass mimicking a hydatid cyst with no relevant medical history, diagnosed at the same time for typical clinical NF1, CT scan showed the cystic mass but did not confirmed its origin, a complete resection of the mass with no capsule fraction was tricky but successful and the histopathology found a high risk of recurrences. The 2 patients received adjuvant imatinib therapy with recurrence free survival at 12 months follow up. Our cases represents a rare entity (multiples GISTs and cystic GIST) within a rarest population (NF1 associated GIST).

DISCUSSION

the diagnosis of NF1 is based on typical clinical criterias but the GISTs are known to be the variable, symptomatic or silent, small size or giant. Imaging is based on CT scan with intravenous contrast studying the vascular pattern, the extra intestinal and metastasis localizations. MRI is no superior, but useful in the study of pelvic GISTs and liver metastasis. Histopathology is the only way to confirm the diagnosis with marker staining with CD117 and DOG-1. The emerging imatinib, sunitinib and regorafinib are used as neoadjuvant or adjuvant therapies in GISTs with high or moderate risk of recurrences. No consensual guidelines are yet established for the follow up as the recurrences are more frequent.

CONCLUSION

GIST's association to NF1 is established, but the different aspects of the physiopathological, clinical and the treatment haven't been established yet with no larger population to study. We believe that the understanding of the development of this type of tumors within the NF type 1 group would allow a better treatment and follow up and may be can lead to screening.

Meta-Analysis on the Efficacy and Safety of Laparoscopic Surgery for Large Gastric Gastrointestinal Stromal Tumors

BACKGROUND

The aim of this study was to conduct a meta-analysis comparing the safety and feasibility of laparoscopic versus open resection for gastric gastrointestinal stromal tumors (GISTs) larger than 5 cm.

METHOD

We searched the Cochrane Library, PubMed, and Embase for relevant articles. Randomized and nonrandomized clinical trials were identified and included in this study. Searching for related articles on large GIST (>5 cm) for laparoscopic resection (laparoscopic group [LAPG]) and open resection (open group [OG]), RevMan 5.3 was used for data analysis, comparing 2 groups of operation time, intraoperative blood loss, complications, length of hospital stay, recurrence rate, disease-free survival, and overall survival.

RESULTS

Seven studies including 440 patients were identified for the meta-analysis. Meta-analysis revealed that LAPG had less bleeding, shorter postoperative hospital stay, and a better 5-year disease-free survival. There was no significant difference between LAPG and OG in operation time, postoperative complications, recurrence rate, and overall survival.

CONCLUSION

Laparoscopic resection of large (>5 cm) GIST is safe and feasible and has the advantages of less intraoperative blood loss and fast postoperative recovery, with a good outcome in the recent oncology.

Correlation between Three-Dimensional Volume and Malignant Potential of Gastrointestinal Stromal Tumors (GISTs)

Background and purpose: Gastrointestinal stromal tumors (GISTs) are rare diseases of the gastrointestinal tract but they are the most common gastrointestinal tumors of mesenchymal origin. Since most GISTs have malignant potential, their probability of malignant progression must be evaluated. This study was conducted to examine the correlation between three-dimensional GIST volume measured by CT and malignant potential. Materials and methods: A retrospective study was performed on 70 patients diagnosed with GIST after surgical resection in Hanyang University Seoul Hospital from 2012 to 2017. Linear regression analysis was used to establish which between the length of the long axis of GISTs, originally considered a predictor of malignancy, and their volume was a more accurate predictor of malignancy. Tumor dimensions were measured by CT. Results: Data were analyzed using the chi-square test or Student’s t-test and logistic regression. Of the GISTs, 53 (75.71%) were in the stomach, 3 (4.29%) in the small intestine, and 14 (20.0%) in the large intestine. The mean age of the malignant GIST group was significantly higher than that of the benign GIST group (p = 0.032), their tumor long axes were significantly greater (p = 0.073), their tumor volumes were significantly larger (p = 0.001), and the frequency of tumor necrosis was higher (p = 0.001). In multivariate analysis, malignant GIST was associated with location in organs other than the stomach (OR 7.846, 95% CI 1.293–47.624, p = 0.025), longer axis (OR 1.037, 95% CI 1.011–1.065, p = 0.006), larger volume (OR 1.003, 95% CI 1.000–1.006, p = 0.029), and necrosis (OR 12.222, 95% CI 1.945–76.794, p = 0.008). The mean age of the recurrent GIST group was higher than that of the non-recurrent group (p = 0.045), their tumor long axes were significantly longer (p = 0.005), and their volumes were greater, but this last difference was not significant (p = 0.072). Conclusions: Tumor volume can be considered an additional risk factor in assessing the malignant potential of GISTs and tends to increase in recurrent GISTs.

Nodular Spindle Cell Vascular Transformation in Pelvic Lymph Nodes With Discovered on GIST1 (DOG1) Positivity Mimicking Metastatic Gastrointestinal Stromal Tumor

We present a case report of vascular transformation of lymph node sinuses (VTS) of nodular spindle cell variant. This variation is a rare, benign entity previously described with histopathologic transformation of lymph node sinuses into spindle cell nodules with or without vascular channels and associated sinusoidal fibrosis. This case highlights the diagnostic pitfall of discovered on GIST1 (DOG1) immunohistochemical staining of this entity, contributing to the initial misdiagnosis as metastatic gastrointestinal stromal tumor (GIST). To our knowledge, this is the first reported case of a patient with VTS and DOG1 positivity. 

Total laparoscopic segmental gastrectomy for gastrointestinal stromal tumors: A case report

BACKGROUND

Gastrointestinal stromal tumors are lesions that originate from digestive tract walls. Several laparoscopic techniques, including local resections, wedge resections and partial gastrectomies, have been used successfully. However, there are no reports on laparoscopic segmental gastrectomy for gastrointestinal stromal tumors.

CASE SUMMARY

We present our analysis of 17 patients who were admitted to our hospital from January 2014 to December 2018. All tumors were located in the corpus and antrum of the stomach, close to the lesser curvature of the stomach. The tumors originated from the anterior wall in nine cases and from the posterior wall of the stomach in eight cases. Laparoscopic segmental gastrectomy and end-to-end anastomosis between the proximal and the distal residual stomach were used in all patients. The mean operative time was 112.4 min. The mean length of hospital stay was 4.6 d. Mean operative blood loss was 73.5 mL. There were no leaks, no postoperative bleeding nor need for reintervention. Mean postoperative follow-up was 35.4 mo. The Visick grading index showed fewer gastrointestinal symptoms 3 mo after surgery. Two patients (11.8%) had reflux esophagitis and gastritis.

CONCLUSION

Laparoscopic segmental gastrectomy may be a new function-preserving gastrectomy that is feasible for treatment of gastrointestinal stromal tumors that grow in the middle third of the stomach and on the lesser stomach curvature.

Lidocaine inhibits vascular endothelial growth factor-A-induced angiogenesis

PURPOSE

Angiogenesis is closely related to the pathophysiology of diseases such as cancer or ischemia. Here, we investigated the effect of lidocaine at clinically effective blood concentrations on vascular endothelial growth factor A (VEGF-A)-induced angiogenesis. In addition, we aimed to clarify the mechanisms by which lidocaine could inhibit angiogenesis.

METHODS

Angiogenesis was analyzed using commercially available in vitro assay kits in human umbilical vein endothelial cells (HUVECs)/normal human dermal fibroblast co-culture systems. The effects of lidocaine on cytotoxicity, VEGF-induced cell migration, and VEGF-induced cell proliferation were examined in HUVECs using lactate dehydrogenase cytotoxic, Boyden chamber, and WST-8 assays, respectively. The VEGF signaling pathway via VEGF receptor 2 (VEGFR-2) was analyzed by western blotting.

RESULTS

Lidocaine elicited a significant dose-dependent, angiogenesis-inhibitory effect at a concentration range of 1-10 μg/ml. At this concentration range, cell death was not observed. Lidocaine, at a concentration of 10 μg/ml, significantly inhibited cell proliferation but not cell migration, induced by VEGF-A in HUVECs. Furthermore, lidocaine, in a dose-dependent manner, significantly inhibited the VEGF-A-induced phosphorylation of VEGFR-2 at 3 and 10 μg/ml.

CONCLUSION

We demonstrated that lidocaine has an anti-angiogenesis effect on clinically effective blood concentrations without causing cell death. This finding could represent a new avenue for future research into anesthesia, cancer-related analgesia, and revascularization therapy.

Histopathological landscape of rare oesophageal neoplasms

The landscape of neoplastic pathology of the oesophagus is dominated by malignancies of epithelial origin, in particular by oesophageal adenocarcinoma and oesophageal squamous cell carcinoma. However, several other histopathological variants can be distinguished, some associated with peculiar histopathological profiles and prognostic behaviours and frequently underrecognized in clinical practice. The aim of this review is to provide a comprehensive characterization of the main morphological and clinical features of these rare variants of oesophageal neoplastic lesions.

Technical Evaluation of Commercial Mutation Analysis Platforms and Reference Materials for Liquid Biopsy Profiling

Molecular profiling from liquid biopsy, in particular cell-free DNA (cfDNA), represents an attractive alternative to tissue biopsies for the detection of actionable targets and tumor monitoring. In addition to PCR-based assays, Next Generation Sequencing (NGS)-based cfDNA assays are now commercially available and are being increasingly adopted in clinical practice. However, the validity of these products as well as the clinical utility of cfDNA in the management of patients with cancer has yet to be proven. Within framework of the Innovative Medicines Initiative (IMI) program CANCER-ID we evaluated the use of commercially available reference materials designed for ctDNA testing and cfDNA derived from Diagnostic Leukaphereses (DLA) for inter- and intra-assay as well as intra- and inter-laboratory comparisons. In three experimental setups, a broad range of assays including ddPCR, MassARRAY and various NGS-based assays were tested. We demonstrate that both reference materials with predetermined VAFs and DLA samples are extremely useful for the performance assessment of mutation analysis platforms. Moreover, our data indicate a substantial variability of NGS assays with respect to sensitivity and specificity highlighting the importance of extensive validation of the test performance before offering these tests in clinical routine practice.

Optimal Endoscopic Resection Technique for Selected Gastric GISTs. The Endoscopic Suturing System Combined with ESD-a New Alternative?

Background and Study Aim: In terms of therapeutic management, gastrointestinal stromal tumors (GISTs) seem to be the most difficult group of subepithelial gastrointestinal lesions (SELs). Despite various treatment option, choice of optimal management remains a dilemma in daily practice. Our aim was to evaluate a new hybrid resection technique of gastric GISTs type III as a modality of endoscopic full-thickness resection. Methods: Three males and one female (mean age of 68) were qualified for the procedure. Endoscopic full-thickness resections consisted of the endoscopic resection combined with suturing by Apollo OverStitch System. The main inclusion criterium was a complete diagnosis of GISTs (computed tomography (CT), endoscopic ultrasound (EUS), fine-needle biopsy (FNB)) with the evaluation of the tumor features, especially, the location in the gastric wall. All of the tumors were type III with a diameter between 20–40 mm. The lesions were located in the corpus (1), antrum (1) and between gastric body and fundus (2). All procedures were performed in 2019. Results: The technical and therapeutic success rate was 100% and the mean resection time 107.5 min. Neither intra- nor postprocedural complications were observed. In all four cases, R0 resection was achieved. Histopathologic assessment confirmed GIST with <5mitose/50HPF in all of the tumors, with very low risk. Conclusion: Based on our outcomes, endoscopic resection combined with the sewing by Apollo OverStitch of gastric GISTs type III, with the diameter between 20–40 mm, seems to be an effective therapeutic option with a good safety profile, however further studies with a larger treatment group are needed.

Different Toxicity Profiles Predict Third Line Treatment Efficacy in Metastatic Colorectal Cancer Patients

The nucleoside trifluridine/tipiracil (TAS-102) and the multikinase inhibitor regorafenib significantly improved survival in metastatic colorectal cancer patients (mCRC). Both treatments are characterized by different treatment-related adverse events but detailed analyses of predictive side effects are rare. In this retrospective, observational, real-life study, clinical data on mCRC patients treated with trifluridine/tipiracil or regorafenib at the Medical University of Vienna, Austria and the University Hospital Zurich, Switzerland were collected. The correlation between adverse events and response or survival rates were calculated performing Fisher’s exact test and log-rank test, respectively. Common adverse events of any grade included fatigue (52%), nausea/vertigo (34%), anemia (26%), and leukopenia (22%) in trifluridine/tipiracil patients and fatigue (42%), hand-foot-skin syndrome (36%) and hoarseness (34%) in patients upon regorafenib treatment. In trifluridine/tipiracil patients the prevalence of leukopenia (p = 0.044) and weight loss (p = 0.044) was prognostic, whereas leukopenia (p = 0.044) and neutropenia (p = 0.043) predicted PFS. The disease control rate was not significantly affected. In regorafenib-treated patients, the prevalence of nausea (p = 0.001) was prognostic, while oral mucositis predicted PFS (p = 0.032) as well as the DCR (p = 0.039). In conclusion, we underline the efficacy of trifluridine/tipiracil and regorafenib in the real-life setting. We describe predictive adverse events like neutropenia/leukopenia, which might be used as surrogate marker in anticancer therapy beyond second line treatment.

Reveal the Regulation Patterns of Prognosis-Related miRNAs and lncRNAs Across Solid Tumors in the Cancer Genome Atlas

BACKGROUND

The dysregulation of non-coding RNAs (ncRNAs) such as miRNAs and lncRNAs are associated with the pathogenesis and progression in multiple cancers including solid tumors. Comprehensive investigations of prognosis-related ncRNA markers could promote the development of therapeutic strategies for solid tumors, but rarely reported.

METHODS

By taking advantage of The Cancer Genome Atlas (TCGA), pan-cancer prognosis analysis (PCPA) models were firstly constructed based on miRNA and lncRNA expression profiles of 8,450 samples in 19 solid tumors. Further, the co-occurrence and exclusivity among ncRNA markers were systematically analyzed for different cancers.

RESULTS

In identified ncRNA makers, 71% of the miRNA markers were shared in multiple cancers, whereas 96% of the lncRNA markers were cancer-specific. Moreover, to analyze the regulation patterns of prognosis-related ncRNAs at the pan-cancer level, miRNA markers were further annotated into eight carcinogenic pathways. Results represented that approximately 86% of these miRNA markers could regulate the PI3K-Akt signaling pathway, while only 48% for the Notch signaling pathway. Finally, among 126 common genes that participated in eight carcinogenic pathways, BCL2, CSNK2A1, EGFR, PDGFRA, and VEGFA were proposed as potential drug targets for multiple cancers.

CONCLUSION

The prognosis analysis and regulation characteristics of ncRNAs presented in this study may help to facilitate the discovery of anti-cancer drugs for multiple solid tumors.

Establishment of patient-derived xenografts from patients with gastrointestinal stromal tumors: analysis of clinicopathological characteristics related to engraftment success

Patient-derived xenografts (PDXs) can represent the heterogeneity and histological characteristics of tumors and are thus useful for testing the efficacy of anti-cancer drugs; however, PDXs are difficult to generate, especially for gastrointestinal stromal tumor (GIST). We analyzed the clinicopathologic factors associated with the successful establishment of GIST PDX in NOD.Cg-Prkdc^scid IL2rg^tm1Wjl/SzJ mice. We used 185 GIST tumor fragments from patients who underwent surgical resection prior to (n = 66; 35.7%) and after treatment (n = 119; 64.3%) with tyrosine kinase inhibitors. The overall success rate of PDX establishment was 17%; in univariate analysis, engraftment success was associated with after TKI treatment, larger tumor size, higher mitotic count, higher Ki-67 index, higher cellularity, presence of tumor necrosis, primary mutations in KIT exon 11, and originating from metastatic lesions. In multivariate analysis, higher Ki-67 index, after TKI treatment, and larger tumor size were independent factors for engraftment success. Immunohistochemistry in representative samples further corroborated the above results. These results will be useful in the establishment of PDX models from GISTs.

Molecular Diagnostic of Solid Tumor Using a Next Generation Sequencing Custom-Designed Multi-Gene Panel

Next generation sequencing (NGS) allows parallel sequencing of multiple genes at a very high depth of coverage. The need to analyze a variety of targets for diagnostic/prognostic/predictive purposes requires multi-gene characterization. Multi-gene panels are becoming standard approaches for the molecular analysis of solid lesions. We report a custom-designed 128 multi-gene panel engineered to cover the relevant targets in 22 oncogene/oncosuppressor genes for the analysis of the solid tumors most frequently subjected to routine genotyping. A total of 1695 solid tumors were analyzed for panel validation. The analytical sensitivity is 5%. Analytical validation: (i) Accuracy: sequencing results obtained using the multi-gene panel are concordant using two different NGS platforms and single-gene approach sequencing (100% of 83 cases); (ii) Precision: consistent results are obtained in the samples analyzed twice with the same platform (100% of 20 cases). Clinical validation: the frequency of mutations identified in different tumor types is consistent with the published literature. This custom-designed multi-gene panel allows to analyze with high sensitivity and throughput 22 oncogenes/oncosuppressor genes involved in diagnostic/prognostic/predictive characterization of central nervous system tumors, non-small-cell lung carcinomas, colorectal carcinomas, thyroid nodules, pancreatic lesions, melanoma, oral squamous carcinomas and gastrointestinal stromal tumors.

Molecular profiling for precision cancer therapies

The number of druggable tumor-specific molecular aberrations has grown substantially in the past decade, with a significant survival benefit obtained from biomarker matching therapies in several cancer types. Molecular pathology has therefore become fundamental not only to inform on tumor diagnosis and prognosis but also to drive therapeutic decisions in daily practice. The introduction of next-generation sequencing technologies and the rising number of large-scale tumor molecular profiling programs across institutions worldwide have revolutionized the field of precision oncology. As comprehensive genomic analyses become increasingly available in both clinical and research settings, healthcare professionals are faced with the complex tasks of result interpretation and translation. This review summarizes the current and upcoming approaches to implement precision cancer medicine, highlighting the challenges and potential solutions to facilitate the interpretation and to maximize the clinical utility of molecular profiling results. We describe novel molecular characterization strategies beyond tumor DNA sequencing, such as transcriptomics, immunophenotyping, epigenetic profiling, and single-cell analyses. We also review current and potential applications of liquid biopsies to evaluate blood-based biomarkers, such as circulating tumor cells and circulating nucleic acids. Last, lessons learned from the existing limitations of genotype-derived therapies provide insights into ways to expand precision medicine beyond genomics.

Anti-tumoral activity of single and combined regorafenib treatments in preclinical models of liver and gastrointestinal cancers

Regorafenib is a sorafenib-derived chemotherapy drug belonging to the multikinase inhibitor family. This agent effectively targets a wide range of tyrosine kinases involved in cancer biology, such as those implicated in oncogenesis, angiogenesis, and tumor microenvironment control. The beneficial effects of regorafenib in clinical trials of patients who suffer from advanced hepatocellular carcinoma (HCC), colorectal cancer (CRC) or gastrointestinal stromal tumors (GISTs) refractory to standard treatments led to regorafenib monotherapy approval as a second-line treatment for advanced HCC and as a third-line treatment for advanced CRC and GISTs. Multiple in vitro and in vivo studies have been performed over the last decade to reveal the molecular mechanisms of the favorable actions exerted by regorafenib in patients. Given the hypothetical loss of sensitivity to regorafenib in tumor cells, preclinical research is also searching for novel therapeutic approaches consisting of co-administration of this drug plus other agents as a strategy to improve regorafenib effectiveness. This review summarizes the anti-tumor effects of regorafenib in single or combined treatment in preclinical models of HCC, CRC and GISTs and discusses both the global and molecular effects that account for its anti-cancer properties in the clinical setting.

The cancer drug regorafenib exhibits a broad range of anti-tumor activities that could be enhanced by combination with other treatments. A team led by José L. Mauriz from the University of León, Spain, review the ways in which regorafenib, blocking several enzymes involved in cancer biology, has been shown to shrink tumors in different models of liver, colon and gastrointestinal cancer. Its mechanisms of action include blockade of new blood vessel formation, induction of cell death and modulation of the immune microenvironment. Research studies show that co-administration of regorafenib with other drugs directed at various molecular targets or immune pathways produces synergistic effects against cancer cells. The preclinical data highlights the potential of combination drug regimens to improve outcomes among patients eligible for regorafenib treatment.

Intestinal tumors in neurofibromatosis 1 with special reference to fatal gastrointestinal stromal tumors (GIST)

Background

Type 1 neurofibromatosis (NF1) is a genetic tumor predisposing Rasopathy. NF1 patients have an increased risk for developing benign and malignant tumors, but the occurrence of intestinal tumors has not been investigated at the population level.

Methods

In this retrospective register‐based total population study, diagnoses of gastrointestinal tract tumors were retrieved from the Finnish Care Register for Health Care for 1,410 NF1 patients and 14,030 reference persons. We also reviewed the death certificates of 232 NF1 patients who died during years 1987–2013, and specifically searched for diagnosis of gastrointestinal stromal tumor (GIST).

Results

The register analysis revealed an increased overall hazard ratio (HR) of 2.6 (95% CI 1.9–3.6) for intestinal tumors in NF1 compared to general population. The highest HR of 15.6 (95% CI 6.9–35.1) was observed in the small intestine. The focused analysis of NF1 death certificates and GISTs demonstrated that the GIST was the primary cause of death in seven patients.

Conclusion

This study emphasizes the need for careful evaluation of NF1 patients with gastrointestinal complaints. The challenge in diagnosis is that the tumors preferably occur at the small intestine, which is difficult target for diagnostic procedures. We also show that the NF1 GISTs may lead to fatal outcome despite of benign histopathological findings at the time of the diagnosis.

Acute Right Lower Abdomen in a Patient with a History of Gastrointestinal Stromal Tumor

Background

Gastrointestinal stromal tumor (GIST) is an uncommon tumor of the GI tract usually seen in elderly patients, often difficult to diagnose because of the unspecific symptoms such as abdominal pain and fullness. Recurrent GIST may have an even more obscure clinical presentation.

Case Report

A 44-year-old female with a history of surgically treated GIST presented to the emergency room complaining of acute onset sharp RLQ pain, nausea, and vomiting. Clinically, she had RLQ tenderness with rebound, her WBC was elevated, and CT scan showed signs of appendicitis and also soft tissue masses suspicious for malignancy. After contemplating treatment options including antibiotics and further workup, it was recommended to proceed with surgery. Laparoscopy showed a thickened appendix with nodular infiltration and multiple mass-like lesions in the RLQ not amendable to minimal invasive resection. From a lower midline incision, an open appendectomy and excision of multiple masses in the terminal ileum and in the abdominal wall were done. Narrow-based Meckel's diverticulum with multiple nodular lesions was also removed. Pathology identified appendicitis and serosal involvement of GIST in all specimens staining positive for CD68, CD117, and vimentin. The patient was started on imatinib and remained recurrence-free after 6 months.

Conclusions

This case illustrates a rare presentation of acute symptomatic recurrent metastatic GIST. Our patient was unusually young, and GIST recurrence presented with acute RLQ pain suggestive for acute appendicitis and also involved Meckel's diverticulum. Surgical debulking followed by imatinib seems to be a reasonable approach in such cases.

A new nomogram for recurrence-free survival prediction of gastrointestinal stromal tumors: Comparison with current risk classification methods

BACKGROUND

This study aimed to build a new risk stratification nomogram for gastrointestinal stromal tumors (GISTs) focused on a popular factor Ki-67 to enable individualized and precise predictions of the most suitable candidates for imatinib therapy.

METHODS

We retrospectively collected clinicopathologic data of the patients diagnosed with GISTs from January 1998 to December 2015 at Southern Medical University Nanfang Hospital as the experiment group. And patients with GISTs at the Sun Yat-sen University Cancer Center from January 2007 to December 2012 were included as the validation group. The nomogram was built using Kaplan-Meier method and the Cox proportional hazards regression model. The receiver operating characteristic (ROC) curves were established to compare the discriminative ability of the new nomogram with other risk stratification systems, including the modified National Institute of Health (modified NIH) criteria, Armed Forces Institute of Pathology (AFIP) criteria, Memorial Sloan Kettering Cancer Center (MSKCC) prognostic nomogram, and contour maps.

RESULTS

In univariate analysis, the tumor size, site, mitotic count, tumor rupture and Ki-67 labeling index were significant factors (all P < 0.05) and included in the Cox model to build our nomogram. According to the ROC curve, our new nomogram showed the largest AUC value (0.778) compared with that of the other classification methods (contour maps, AUC = 0.743; AFIP, AUC = 0.719; MSKCC, AUC = 0.712; and modified NIH, AUC = 0.719).

CONCLUSION

Our new nomogram exhibits an excellent performance and might become a potential risk stratification to support therapeutic decision-making for GISTs.

The identification of patient-specific mutations reveals dual pathway activation in most patients with melanoma and activated receptor tyrosine kinases in BRAF/NRAS wild-type melanomas

BACKGROUND

Increasing knowledge of cancer genomes has triggered the development of specific targeted inhibitors, thus providing a valuable therapeutic pool.

METHODS

In this report, the authors analyze the presence of targetable alterations in 136 tumor samples from 92 patients with melanoma using a comprehensive approach based on targeted DNA sequencing and supported by RNA and protein analysis. Three topics of high clinical relevance are addressed: the identification of rare, activating alterations; the detection of patient-specific, co-occurring single nucleotide variants (SNVs) and copy number variations (CNVs) in parallel pathways; and the presence of cancer-relevant germline mutations.

RESULTS

The analysis of patient-matched blood and tumor samples was done with a custom-designed gene panel that was enriched for genes from clinically targetable pathways. To detect alterations with high therapeutic relevance for patients with unknown driver mutations, genes that are untypical for melanoma also were included. Among all patients, CNVs were identified in one-third of samples and contained amplifications of druggable kinases, such as CDK4, ERBB2, and KIT. Considering SNVs and CNVs, 60% of patients with metastases exhibited co-occurring activations of at least 2 pathways, thus providing a rationale for individualized combination therapies. Unexpectedly, 9% of patients carry potentially protumorigenic germline mutations frequently affecting receptor tyrosine kinases. Remarkably two-thirds of BRAF/NRAS wild-type melanomas harbor activating mutations or CNVs in receptor tyrosine kinases.

CONCLUSIONS

The results indicate that the integrated analysis of SNVs, CNVs, and germline mutations reveals new druggable targets for combination tumor therapy.

Prolonging Gastrointestinal-Stromal-Tumor-free life, an optimal suggestion of imatinib intervention ahead of operation

Background: Imatinib has been regarded as the first successful synthetic small molecule targeting at blocking tyrosine kinase. Its high efficacy stabilized disease in above 80% of chronic myeloid leukemia (CML) patients over 10 years survival. Due to the similar canceration of gastrointestinal stromal tumor (GIST) as to CML, imatinib has been approved to be used as first-line treatment. Study design: Our retrospective study was proposed to enroll 191 GIST patients with larger tumor size (≥8 cm) who preoperative accepted imatinib from those with direct operation. Analysis included demographics, cancer specific survival and relationship of their risk factors. Results: Male patients and gastrointestinal (GI) tract location took higher proportion in total cases, detection of KIT mutant took 89.7% among all traceable genetic testing. Patients with preoperative imatinib can achieve higher cancer specific survival (CSS) after both in 1 year and 3 years duration than their counterpart. Tumor size above its threshold of 8 cm would be a hazardous factor for poor prognosis. Conclusion: In conclusion, as for regressing tumor progression and creating operative chance, preoperative imatinib should be considered for the patients with high risk, although the precise duration of this intervention needs further validation.

Management of Advanced Small Bowel Cancer

OPINION STATEMENT

Small bower cancer is a rare disease, despite its incidence is increasing in the last decade. Both benign and malignant tumors can arise from the small intestine. The main histological cancer types are adenocarcinomas, neuroendocrine tumors, sarcomas, gastrointestinal stromal tumors (GISTs), and lymphomas. Due to the rarity of these malignances, all the currently available data are based on small studies or retrospective series, although recent breakthroughs are redirecting our approach to these patients. Immunotherapy for small bowel adenocarcinomas, several multikinase inhibitors in resistant GIST patients, as well as everolimus and ¹⁷⁷Lu-DOTATATE in neuroendocrine tumors are only few of the novel therapeutic options that have changed, or may change in the future, the therapeutic landscape of these rare cancers. Larger and more powerful studies on the molecular profile of these tumors may lead to a better design of clinical trials, which eventually would provide our patients with more efficacious treatments to improve both overall survival and quality of life.

Neomorphic PDGFRA extracellular domain driver mutations are resistant to PDGFRA targeted therapies

Activation of platelet-derived growth factor receptor alpha (PDGFRA) by genomic aberrations contributes to tumor progression in several tumor types. In this study, we characterize 16 novel PDGFRA mutations identified from different tumor types and identify three previously uncharacterized activating mutations that promote cell survival and proliferation. PDGFRA Y288C, an extracellular domain mutation, is primarily high mannose glycosylated consistent with trapping in the endoplasmic reticulum (ER). Strikingly, PDGFRA Y288C is constitutively dimerized and phosphorylated in the absence of ligand suggesting that trapping in the ER or aberrant glycosylation is sufficient for receptor activation. Importantly, PDGFRA Y288C induces constitutive phosphorylation of Akt, ERK1/2, and STAT3. PDGFRA Y288C is resistant to PDGFR inhibitors but sensitive to PI3K/mTOR and MEK inhibitors consistent with pathway activation results. Our findings further highlight the importance of characterizing functional consequences of individual mutations for precision medicine.

A 4-month-old boy with gastrointestinal stromal tumor of mesocolon

Gastrointestinal stromal tumors (GISTs) are very uncommon in pediatric patients, and they are distinct clinical-pathological and molecular deviations from their adult counterparts. Most pediatric GISTs lack the c-kit or platelet-derived growth factor receptor alpha (PDGFRA) genes mutations. To date, there is no published standard guidelines available for the best treatment of pediatric GISTs, especially for infant GIST. Therefore, we report a case of 4-month-old infant with GIST of mesocolon without KIT/PDGFRA mutation. We also review the clinical, biological, and genetic features of pediatric GISTs and re-think several questions that could affect clinical practice.

Small bowel gastrointestinal stromal tumor: a retrospective study of 32 cases at a single center and review of the literature

Background

Gastrointestinal stromal tumor (GIST) is a rare tumor of the small bowel, which can be difficult to diagnose and has a varied clinical outcome.

Purpose

This is a retrospective review of the diagnosis, management, and clinical outcome of 32 patients diagnosed with primary small bowel GIST from a single center and a comparison of the findings with previously published cases.

Patients and methods

Retrospective review of data from patient clinical records, endoscopic and imaging findings, surgical procedures, tumor histology and immunohistochemistry, and clinical outcome was conducted.

Results

Data of 32 patients with a median age of 56 years including 50% men and women were reviewed. The majority (29/32) were symptomatic at presentation, with the main symptom being gastrointestinal bleeding (15/32). Imaging detection rates included ultrasound (0%), magnetic resonance imaging (0%), computed tomography (54.8%), computed tomography angiography (71.4%), and double-balloon enteroscopy (88.9%). The mean tumor diameter was 5.3 cm; 4 tumors were located in the duodenum, 21 in the jejunum, and 7 in the ileum. Based on the tumor size and mitotic index, 5 (15.6%), 15 (46.9%), 0 (0%), and 12 (37.5%) patients were classified into very low-risk, low-risk, intermediate-risk, and high-risk groups. Immunohistochemistry showed positive expression for CD117 (100%), CD34 (81.2%), DOG1 (93.8%), smooth muscle actin (37.5%), S100 (9.4%), and desmin (6.2%). Twenty-five patients (78.1%) were treated with open surgical tumor resection; seven patients (21.9%) underwent laparoscopic surgery. Postoperative complications that occurred in seven patients (21.9%) were resolved with conservative management. Four patients were treated with postoperative imatinib. At median follow-up of 30 months, two patients were died.

Conclusion

The findings from this case series, combined with the findings from previously published cases, provide an update on the current status of the diagnosis and the therapeutic approaches that might lead to improvement in prognosis for patients who present with primary small bowel GIST.

Silencing of adaptor protein SH3BP2 reduces KIT/PDGFRA receptors expression and impairs gastrointestinal stromal tumors growth

Gastrointestinal stromal tumors (GISTs) represent about 80% of the mesenchymal neoplasms of the gastrointestinal tract. Most GISTs contain oncogenic KIT (85%) or PDGFRA (5%) receptors. The kinase inhibitor imatinib mesylate is the preferential treatment for these tumors; however, the development of drug resistance has highlighted the need for novel therapeutic strategies. Recently, we reported that the adaptor molecule SH3 Binding Protein 2 (SH3BP2) regulates KIT expression and signaling in human mast cells. Our current study shows that SH3BP2 is expressed in primary tumors and cell lines from GIST patients and that SH3BP2 silencing leads to a downregulation of oncogenic KIT and PDGFRA expression and an increase in apoptosis in imatinib-sensitive and imatinib-resistant GIST cells. The microphthalmia-associated transcription factor (MITF), involved in KIT expression in mast cells and melanocytes, is expressed in GISTs. Interestingly, MITF is reduced after SH3BP2 silencing. Importantly, reconstitution of both SH3BP2 and MITF restores cell viability. Furthermore, SH3BP2 silencing significantly reduces cell migration and tumor growth of imatinib-sensitive and imatinib-resistant cells in vivo. Altogether, SH3BP2 regulates KIT and PDGFRA expression and cell viability, indicating a role as a potential target in imatinib-sensitive and imatinib-resistant GISTs.

Management of hemorrhage in gastrointestinal stromal tumors: a review

Gastrointestinal stromal tumors (GISTs) are relatively common mesenchymal tumors. They originate from the wall of hollow viscera and may be found in any part of the digestive tract. The prognosis of patients with stromal tumors depends on various risk factors, including size, location, presence of mitotic figures, and tumor rupture. Emergency surgery is often required for stromal tumors with hemorrhage. The current literature suggests that stromal tumor hemorrhage indicates poor prognosis. Although the optimal treatment options for hemorrhagic GISTs are based on surgical experience, there remains controversy with regard to optimum postoperative management as well as the classification of malignant potential. This article reviews the biological characteristics, diagnostic features, prognostic factors, treatment, and postoperative management of GISTs with hemorrhage.

Comparison of three prognostic models for predicting cancer-specific survival among patients with gastrointestinal stromal tumors

AIM

To evaluate the predictive value for cancer-specific survival of the models of the American Joint Committee on Cancer (AJCC) stage, NIH and Armed Forces Institute of Pathology (AFIP) among patients with gastrointestinal stromal tumors (GISTs).

METHODS

Surveillance, Epidemiology and End Results database (2010-2014) was accessed. Overall survival analysis and adjusted cancer-specific Cox regression hazard was calculated.

RESULTS

For gastric GISTs, concordance-index according to AJCC was 0.834; according to NIH was 0.833; according to AFIP was 0.836. Concordance-index for nongastric GISTs according to AJCC was 0.800, according to NIH was 0.801 and according to AFIP was 0.799.

CONCLUSION

The performance of the three models is comparable with regards to cancer-specific survival prediction.

Incidence and risk of hematologic toxicities in cancer patients treated with regorafenib

Regorafenib, an oral vascular endothelial growth factor receptor tyrosine-kinase inhibitor, has been approved for the treatment of several malignancies. As a non-traditional cytotoxic chemotherapeutic agent, regorafenib is often associated with hematologic toxicities. Here we searched PubMed and Embase up to June 2017 for relevant clinical trials. Eligible studies include trials in which subjects treated with 160 mg of regorafenib daily during the first 21 days of each 28-day cycle, and adequate safety data profile reporting thrombocytopenia, anemia, neutropenia and leucopenia. Statistical analyses were conducted to calculate the overall incidences, relative risks (RRs) and their 95% confidence intervals (CIs). A total of 2,341 subjects from 16 trials were included in the present studies. The incidences of regorafenib associated all-grade and high-grade hematologic toxicities were: thrombocytopenia, 22% and 3%; anemia, 20% and 3%; neutropenia, 10% and 2%, and leucopenia, 13% and 2%, respectively. Regorafenib-treated subjects had a significant increased risk of all-grade (RR=6.35; 95% CI, 3.19-12.64) and high-grade (RR=6.27; 95% CI, 1.69-23.26) thrombocytopenia, all-grade (RR=2.76; 95% CI, 1.63-4.68) and high-grade (RR=5.38; 95% CI, 1.60-18.06) anemia. Our results suggested that regorafenib therapy was associated with significantly increased risks of hematological toxicities, and hematologic monitoring at regular intervals should be advised to clinician.

Incidence and risk of regorafenib-induced hepatotoxicity

Regorafenib, an oral multi-kinase inhibitor, has been approved for the treatments of several malignancies. Unlike traditional cytotoxic chemotherapeutic agents, regorafenib therapy often induces a distinct profile of adverse events (AEs) including hepatotoxicity. Here we conducted an up-to-date meta-analysis to assess the incidence and risk of regorafenib related hepatic toxicities. PubMed and Embase database were reviewed from inception to June 2017 for relevant trials. Eligible studies include subjects with solid tumors treated with 160 mg of regorafenib daily during the first three week of each four-week cycle, and adequate safety data reporting the elevation of aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin. Statistical analyses were conducted to calculate the summary incidence and relative risk (RR). A total of 2,213 subjects from 14 trials were included. The incidences of regorafenib-associated all-grade and high-grade hepatotoxicity were: bilirubin elevation: 23% and 5%; AST elevation: 32% and 6%; ALT elevation: 27% and 5%; ALP elevation: 31% and 2%. Regorafenib-treated subjects had a significant increased risk of all-grade (RR = 3.10; 95% CI, 2.22–4.34) and high-grade (RR = 1.74; 95% CI, 1.09–2.80) bilirubin elevation; all-grade (RR = 1.51; 95% CI, 1.13–2.00) and high-grade (RR = 1.79; 95% CI, 1.00–3.22) AST elevation; all-grade (RR = 1.82; 95% CI, 1.25–2.64) and high-grade (RR = 3.07; 95% CI, 1.30–7.22) ALT elevation; and all-grade (RR = 2.11; 95% CI, 1.01–4.40) ALP elevation. Our results suggest that regorafenib is associated with an increased risk of hepatic toxicities. Hepatotoxicity examination at regular intervals should be advised to clinicians.