Advances and Challenges on Management of Gastrointestinal Stromal Tumors

Advanced gastrointestinal stromal tumor: reliable classification of imatinib plasma trough concentration via machine learning

AIM

Patients with advanced gastrointestinal stromal tumors (GISTs) exhibiting an imatinib plasma trough concentration (IM Cmin) under 1100 ng/ml may show a reduced drug response rate, leading to the suggestion of monitoring for IM Cmin. Consequently, the objective of this research was to create a customized IM Cmin classification model for patients with advanced GISTs from China.

METHODS

Initial data and laboratory indicators from patients with advanced GISTs were gathered, and the above information was segmented into a training set, validation set, and testing set in a 6:2:2 ratio. Key variables associated with IM Cmin were identified to construct the classification model using the least absolute shrinkage and selection operator (LASSO) regression and forward stepwise binary logistic regression. Within the training and validation sets, nine ML classification models were constructed via the resampling method and underwent comparison through the Brier scores, the areas under the receiver-operating characteristic curve (AUROC), the decision curve, and the precision-recall (AUPR) curve to determine the most suitable model for this dataset. Two methods of internal validation were used to assess the most suitable model's classification performance: tenfold cross-validation and random split-sample validation (test set), and the value of the test set AUROC was used to evaluate the model's classification performance.

RESULTS

Six key variables (gender, daily IM dose, metastatic site, red blood cell count, platelet count, and percentage of neutrophils) were ultimately selected to construct the classification model. In the validation set, it is found by comparison that the Extreme Gradient Boosting (XGBoost) model has the largest AUROC, the lowest Brier score, the largest area under the decision curve, and the largest AUPR value. Furthermore, as evaluated via internal verification, it also performed well in the test set (AUROC = 0.725).

CONCLUSION

For patients with advanced GISTs who receive IM, initial data and laboratory indicators could be used to accurately estimate whether the IM Cmin is below 1100 ng/ml. The XGBoost model may stand a chance to assist clinicians in directing the administration of IM.

Receptor tyrosine kinase gene expression profiling of orbital rhabdomyosarcoma unveils MET as a potential biomarker and therapeutic target

Receptor tyrosine kinases (RTKs) serve as molecular targets for the development of novel personalized therapies in many malignancies. In the present study, expression pattern of receptor tyrosine kinases and its clinical significance in orbital RMS has been explored. Eighteen patients with histopathologically confirmed orbital RMS formed part of this study. Comprehensive q-PCR gene expression profiles of 19 RTKs were generated in the cases and controls. The patients were followed up for 59.53 ± 20.93 years. Clustering and statistical analysis tools were applied to identify the significant combination of RTKs associated with orbital rhabdomyosarcoma patients. mRNA overexpression of RTKs which included MET, AXL, EGFR was seen in 60-80% of cases; EGFR3, IGFR2, FGFR1, RET, PDGFR1, VEGFR2, PDGFR2 in 30-60% of cases; and EGFR4, FGFR3,VEGFR3 and ROS,IGFR1, EGFR1, FGFR2, VEGFR1 in 10-30% of cases. Immunoexpression of MET was seen in 89% of cases. A significant association was seen between MET mRNA and its protein expression. In all the cases MET gene expression was associated with worst overall survival (P = 0.03).There was a significant correlation of MET mRNA expression with RET, ROS, AXL, FGFR1, FGFR3, PDGFR1, IGFR1, VEGFR2, and EGFR3 genes. Association between MET gene and collective expression of RTKs was further evaluated by semi-supervised gene cluster analysis and Principal component analysis, which showed well-separated tumor clusters. MET gene overexpression could be a useful biomarker for identifying high risk orbital rhabdomyosarcoma patients. Well-separated tumor clusters confirmed the association between MET gene and collective expression of RTK genes. Therefore, the therapeutic potential of multi-kinase inhibitors targeting MET and the 9 other significant RTKs needs to be explored.

Unresectable Hepatocellular Carcinoma: A Review of New Advances with Focus on Targeted Therapy and Immunotherapy

With an expected incidence of more than 1 million cases by 2025, liver cancer remains a problem for world health. With over 90% of cases, hepatocellular carcinoma (HCC) is the most prevalent kind of liver cancer. In this review, we presented the range of experimental therapeutics for patients with advanced HCC, the successes and failures of new treatments, areas for future development, the evaluation of dose-limiting toxicity in different drugs, and the safety profile in patients with liver dysfunction related to the underlying chronic liver disease. In addition to the unmet demand for biomarkers to guide treatment decisions and the burgeoning fields of immunotherapy and systemic therapy in hepatocellular carcinoma, the development of old and new drugs, including their failures and current advancements, has been reviewed. This review aims to evaluate the updated optimal clinical treatment of unresectable hepatocellular carcinomas in clinical practice, mainly through targeted therapy. Although surgical treatment can significantly enhance the survival probability of early and intermediate-stage patients, it is unsuitable for most HCC patients due to a lack of donors. Due to their severe toxicity, the few first-line anti-HCC drugs, such as sorafenib, are often reserved for advanced HCC patients for whom other therapies have failed. The second-line drugs are usually alternatives for patients with intolerance or resistance. Consequently, the ongoing growth of possible preclinical drugs and studies on miRNAs, lncRNAs, and numerous other signaling pathway targets for developing novel drugs may introduce additional treatment prospects for HCC.

Self-reported cognitive impairments and quality of life in patients with gastrointestinal stromal tumor: Results of a multinational survey

BACKGROUND

Cancer-related cognitive impairment (CRCI) has long-term effects on survivor quality of life, but CRCI research on patients with gastrointestinal stromal tumor (GIST) is lacking. The aims of this study were to investigate CRCI and concomitant quality of life among patients with GIST.

METHODS

An online survey was used to assess CRCI in adult patients with GIST using the validated Functional Assessment of Cancer Therapy-Cognitive-v.3. Age, education, demographically indexed IQ, general health, and quality of life factors (e.g., fatigue, emotional distress) were also assessed. The online survey was administered through five international GIST and sarcoma support organizations.

RESULTS

Over the 3-month recruitment period, the survey was completed by 485 participants: mean age, 57.80 (SD, 11.51), median 5 years after diagnosis. A majority (63.91%) reported experiencing cognitive symptoms with a significant negative quality of life impact. Controlling for age, patients with GIST ≥5 years after diagnosis reported worse cognitive function than those <5 years after diagnosis (p < .05) but did not differ in educational level or IQ. Whereas longer term survivors were more likely to have been treated with tyrosine kinase inhibitor (TKI) therapies, there was no observed association of TKI therapy with self-reported cognitive impairments.

CONCLUSIONS

A majority of GIST patients report cognitive symptoms that have a negative impact on quality of life, with longer term survivors (≥5 years) tending to report more cognitive impairments. Given the success of TKI therapy to substantially increase overall survival of patients with GIST, addressing CRCI in clinical practice may improve long-term GIST survivor function and quality of life.

Laparoscopic resection is not superior to endoscopic resection for relative small gastric gastrointestinal stromal tumors: A propensity score-matched study

Background and Aim

Endoscopic resection (ER) and laparoscopic resection (LAP) have been recommended for the treatment of gastric gastrointestinal stromal tumors (GISTs) less than 2 cm. However, the therapeutic approach for gastric GISTs between 2 and 5 cm in diameter is still under debate. In this retrospective study, we aimed to evaluate the feasibility, efficacy, and safety of ER for gastric GISTs (2–5 cm) compared with LAP.

Methods

From January, 2011 to January, 2018, 197 patients with GISTs at our institution with tumor diameter between 2 and 5 cm were included in our study. Clinical baseline characteristics, histopathological results, and perioperative outcomes were collected and compared in all the patients. Propensity score matching (PSM) methods were used to balance baseline characteristics.

Results

There was no significant difference in age (p = 0.246), gender (p = 0.572), tumor location (p = 0.333), pathological risk classification (p = 0.543), Ki-67 index (p = 0.212), and follow-up time (p = 0.831) in the ER and LAP groups. However, significance difference was found in times to liquid diet intake (4.45 ± 1.2 vs. 5.40 ± 1.5 days, p = 0.013) and hospital stays (7.72 ± 1.1 vs. 10.01 ± 1.3 days, p &lt; 0.001). During the follow-up period, there was one recurrence in the ER group vs. two recurrences in the LAP group. After PSM, the tumor size was balanced between the two groups with 49 patients in each group. The times to liquid diet intake (4.18 ± 1.3 vs. 5.16 ± 1.6 days, p = 0.042) and hospital stay days (7.12 ± 1.1 vs. 9.94 ± 1.3, p &lt; 0.0001) were still short in the ER group.

Conclusions

ER is more associated with a quick postoperative recovery than LAP. ER could be an alternative approach for gastric GISTs (2–5 cm). However, the long-term follow-up outcomes are still unclear and random control trials are needed.

Duodenal Ampulla Neuroendocrine Tumor with GISTs of the Proximal Jejunum: A Case Report

Neuroendocrine tumors (NEN) are a type of heterogenous, slow-growing tumors, that only in about half of the cases can be found in the gastrointestinal tract. Half of these is in the small intestine. The ampullary NENs are rare, accounting for less than 1% of gastroenteropancreatic NENs. Gastrointestinal stromal tumors (GIST) are a more common type of tumors of the gastrointestinal tract that consist of pacemaker cells. The occurrence of both tumors simultaneously is rare, but in patients with neurofibromatosis type 1, the co-existence of NEN and GIST is more often. Here we report a case of simultaneous occurrence of a well-differentiated NEN and a GIST in a patient without neurofibromatosis. Also, we provide a short review of the current knowledge and treatment strategies regarding these tumors.

Advances in endoscopic resection techniques of small gastric tumors originating from the muscularis propria

Gastrointestinal stromal tumors are common gastrointestinal tumors typically originating from the muscularis propria layer of the stomach. Small gastric stromal tumors are usually detected incidentally during routine endoscopic examination. Although they may have malignant potentially, controversies remain regarding the need for endoscopic resection of small gastric stromal tumors originating from the muscularis propria. According to the guidelines of the European Society of Medical Oncology, all gastrointestinal stromal tumors >2 cm in size should be resected with endoscopic surveillance recommended for tumors <2 cm. Endoscopic resection including endoscopic mucosal dissection (EMD), endoscopic submucosal dissection (ESD), submucosal tunneling endoscopic resection and snare assisted endoscopic resection. However, EMD and ESD procedures may be accompanied with serious complications including perforation, bleeding, and abdominal infection. Snare-assisted endoscopic resection is an alternative approach and has the advantages of a shorter procedure time and a low rate of perforation or bleeding. This study summarizes the safety and feasibility of a novel snare-assisted endoscopic resection technique and highlights the pros and cons of the different endoscopic approaches currently used for subepithelia small gastric tumors.

Clinical and Molecular Characteristics of Rare Malignant Tumors of Colon and Rectum

Simple Summary

Tumors of colon and rectum other than adenocarcinomas represent a neglected issue from clinical and laboratory points of view because of their rarity. In this review, we summarize and describe the rare histologic entities occurring in colon and rectum. Clinical and pathologic characteristics, prognostic behavior, treatments, and altered genes are reported to provide readers with a paramount and comparative perspective. In relation to this, we propose that improvements in registries and multidisciplinary research are warranted to ameliorate their management.

Abstract

The most frequent form of colorectal cancer is represented by adenocarcinoma being about 98% of tumor histological types. However, other rare histotypes can be found in colon and rectum (adenosquamous, goblet cell adenocarcinoma, lymphoma, medullary carcinoma, melanoma, mesenchymal, neuroendocrine, plasmacytoma, signet ring, squamous tumors). Altogether, these forms account for less than 2% of colorectal tumors. There are no specific diagnostic or therapeutic recommended approaches and most of the information available from literature derives from small and retrospective clinical series. In the present study, we provide a paramount and updated view on clinical and biologic characteristics of rare colorectal tumors.

Multiple jejunal gastrointestinal stromal tumors and Neurofibromatosis type 1: A rare association

INTRODUCTION AND IMPORTANCE

The association between gastrointestinal stromal tumor (GIST), mesenchymal tumor arising from the interstitial cells of cajal and Neurofibromatosis type 1 (NF1), an autosomal dominant disease has been reported in the literature. GIST in NF1 patients are multiple and located in the small intestine. Tumorigenesis in NF1 associated GIST is different to that of sporadic GIST and hence the treatment. Here we report a rare case of an NF1 patient with multiple jejunal GISTs.

CASE PRESENTATION

We here present a rare case of a 57-year-old male diagnosed with NF1 30 years back, presented in our emergency department with complaints of black, tarry stools later diagnosed to have multiple GIST in jejunum. Contrast enhanced computed tomography (CECT) of the abdomen showed a large 10.1 × 7.33 × 6.2 cm heterogeneous, exophytic, solid mass with cystic areas originating from the jejunum. The microscopic examination of the specimen showed spindle shaped tumor cells while immunohistochemistry showed CD117 (c-KIT) and DOG-1 positivity. The primary treatment was complete surgical excision of the tumor.

CLINICAL DISCUSSION

The incidence of GISTs in NF1 patient is around 6-7%; however, concomitant presence of multiple GISTs is rare. CECT of abdomen along with histopathological and immunohistochemistry studies are diagnostic. The management of GIST includes surgical and adjuvant therapy methods based on the tumorigenesis and recurrent risk stratification.

CONCLUSION

Early clinical suspicion and imaging aids in early detection of the tumor in patients with NF1 presenting with gastrointestinal symptoms. Postoperatively, screening for recurrence with radiology is of utmost importance.

Discovery and pharmacological characterization of AZD3229, a potent KIT/PDGFRα inhibitor for treatment of gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common human sarcoma driven by mutations in KIT or platelet-derived growth factor α (PDGFRα). Although first-line treatment, imatinib, has revolutionized GIST treatment, drug resistance due to acquisition of secondary KIT/PDGFRα mutations develops in a majority of patients. Second- and third-line treatments, sunitinib and regorafenib, lack activity against a plethora of mutations in KIT/PDGFRα in GIST, with median time to disease progression of 4 to 6 months and inhibition of vascular endothelial growth factor receptor 2 (VEGFR2) causing high-grade hypertension. Patients with GIST have an unmet need for a well-tolerated drug that robustly inhibits a range of KIT/PDGFRα mutations. Here, we report the discovery and pharmacological characterization of AZD3229, a potent and selective small-molecule inhibitor of KIT and PDGFRα designed to inhibit a broad range of primary and imatinib-resistant secondary mutations seen in GIST. In engineered and GIST-derived cell lines, AZD3229 is 15 to 60 times more potent than imatinib in inhibiting KIT primary mutations and has low nanomolar activity against a wide spectrum of secondary mutations. AZD3229 causes durable inhibition of KIT signaling in patient-derived xenograft (PDX) models of GIST, leading to tumor regressions at doses that showed no changes in arterial blood pressure (BP) in rat telemetry studies. AZD3229 has a superior potency and selectivity profile to standard of care (SoC) agents-imatinib, sunitinib, and regorafenib, as well as investigational agents, avapritinib (BLU-285) and ripretinib (DCC-2618). AZD3229 has the potential to be a best-in-class inhibitor for clinically relevant KIT/PDGFRα mutations in GIST.

Pediatric Gastrointestinal Stromal Tumors and Neuroendocrine Tumors: Advances in Surgical Management

Gastrointestinal stromal tumors and neuroendocrine tumors in adult and pediatric populations differ immensely. Despite these established differences, the extreme rarity of gastrointestinal stromal tumors and neuroendocrine tumors in the pediatric population has resulted in the lack of consensus management guidelines, making optimal surgical approaches unclear. Comprehensive management principles to guide surgical approaches in adult literature are extensive. However, these are still lacking for pediatric patients. International cooperation to develop standardized pediatric-specific guidelines is urgently warranted in the future. This article highlights the vast differences between adult and pediatric parameters and provides recommendations on optimal and novel surgical approaches in children.

Rare Occurrence of Microsatellite Instability in Gastrointestinal Stromal Tumors

Background and Objectives: This study aimed to objectively determine microsatellite instability (MSI) status using a next-generation sequencing (NGS)-based MSI panel and to resolve the discrepancy regarding whether or not MSI is a rare phenomenon, irrespective of diverse genomic alterations in gastrointestinal stromal tumors (GISTs). Materials and Methods: Genomic DNA was subjected to MSI panel sequencing using an Ion AmpliSeq Microsatellite Instability Assay, as well as to cancer gene panel sequencing using an Oncomine Focus DNA Assay. Results: All of our GIST patients showed microsatellite-stable (MSS) status, which confirmed that MSI status did not affect the molecular pathogenesis of GIST. The KIT gene (79%, 38/48) was the most frequently mutated gene, followed by the PDGFRA (8%, 4/48), PIK3CA (8%, 4/48), and ERBB2 (4%, 2/48) mutations. KIT exon 11 mutant patients were more favorable in responding to imatinib than those with exon 9 mutant or wild-type GISTs, and compared to non-KIT exon 11 mutant GISTs (p = 0.041). The NGS-based MSI panel with MSICall confirmed a rare phenomenon of microsatellite instability in GISTs irrespective of diverse genomic alterations. Conclusion: Massively parallel sequencing can simultaneously provide the MSI status as well as the somatic mutation profile in a single test. This combined approach may help us to understand the molecular pathogenesis of GIST carcinogenesis and malignant progression.

Comparative Efficacy and Safety of Different Regimens of Advanced Gastrointestinal Stromal Tumors After Failure Prior Tyrosine Kinase Inhibitors: A Network Meta-Analysis

INTRODUCTION

The prospect of targeted therapies for advanced gastrointestinal stromal tumors (GISTs) has been dramatically transformed after encouraging results achieved in recent clinical trials. At present, the number of second- and third-line treatments are increasing, although the challenge is to take into account the differences between these interventions. Therefore, our goal is to evaluate the investigation of different regimens currently used in GISTs based on findings from phase II or phase III randomized controlled trials (RCTs), and then indirectly compare the effectiveness and safety of the available therapies.

METHODS

The qualified literatures in relevant sources were searched systematically. Studies to identify RCTs of which main endpoints were progression-free survival (PFS), overall survival (OS), and grade 3 or more adverse events (AEs) in patients with GISTs were considered for inclusion.

RESULTS

Eight RCTs met our inclusion criteria, which involved 2351 patients. For PFS, compared with placebo, imatinib, and sunitinib, regorafenib (HR = 0.12, 95% CI 0.07-0.23; HR = 0.27, 95% CI 0.19-0.39; HR = 0.36, 95% CI 0.19-0.72, respectively) and ripretinib (HR = 0.15, 95% CI 0.09-0.25; HR = 0.33, 95% CI 0.16-0.68; HR = 0.44, 95% CI 0.25-0.78, respectively) were significantly correlated with the improvement of PFS, and regorafenib may be the preferred option according to the analysis of treatment rankings. For OS, compared with placebo, imatinib, and sunitinib, masitinib (HR = 0.13, 95% CI 0.04-0.44; HR = 0.13, 95% CI 0.04-0.51; HR = 0.27, 95%CI 0.09-0.84) and ripretinib (HR = 0.36, 95% CI 0.21-0.62; HR = 0.36, 95% CI 0.16-0.80; HR = 0.18, 95% CI 0.09-0.36, respectively) were significantly more effective, and masitinib may be the best choice according to treatment ranking analysis. Statistically, regorafenib can be considered to be the highest in high-grade AEs, while the rate of severe AEs of ripretinib and masitinib was likely the lowest.

CONCLUSION

Our results show that ripretinib has the most favorable balance between effectiveness and tolerability among the different treatment regimens for GISTs.

Comparison of endoscopic versus laparoscopic resection for gastric gastrointestinal stromal tumors: A preliminary meta-analysis

BACKGROUND AND AIM

For localized disease, complete surgical resection is regarded as the "gold standard" therapeutic modality. With the rapid development of endoscopic techniques, endoscopic resection (ESR) has been confirmed as an efficient and safe alternative for the treatment of gastrointestinal stromal tumors (GISTs) in the stomach. Nevertheless, the management of gastric GISTs remains poorly defined. The purpose of this study is to evaluate the security and effectiveness of ESR with laparoscopic resection (LAR) for gastric GISTs.

METHODS

A literature search of online databases was conducted to identify relevant comparative studies of ESR and LAR procedures for gastric GISTs published before April 10, 2020. The cumulative data analysis was also performed utilizing the software STATA.

RESULTS

In total, 10 studies involving 1165 patients met the inclusion criteria for analysis (651 for ESR and 514 for LAR). From the results of meta-analysis, patients who underwent ESR experienced decreased operative time (P = 0.000), less intraoperative blood loss (P = 0.002), earlier time to diet (P = 0.000), shorter hospital stay (P = 0.000), and lower total charges (P = 0.000) compared with LAR. Moreover, there were no significant differences between these two approaches concerning tumor rupture, conversion rate to other procedure, complete resection rate, postoperative complication rate, recurrence rate, and disease-free survival.

CONCLUSIONS

Endoscopic resection, as an effective alternative treatment strategy with satisfactory outcomes, is acceptable for selective patients with gastric GISTs compared with LAR. Further well-designed randomized controlled trials with large samples are warranted to corroborate our observations.

A multi-class scoring system based on CT features for preoperative prediction in gastric gastrointestinal stromal tumors

Our study aimed to establish and validate a multi-class scoring system for preoperative gastric gastrointestinal stromal tumors (GISTs) risk stratifications based on CT features. 150 gastric GIST patients who underwent contrast-enhanced CT examination and surgical resection from hospital 1 were retrospectively analyzed as the training cohort, and 61 patients from hospitals 2 and 3 were included as the validation cohort. A model was established by logistic regression analysis and weighted to be a scoring model. A calibration test, area under the receiver operating characteristic (ROC) curve (AUC), and cutoff points were determined for the score model. The model was also divided into three score ranges for convenient clinical evaluation. Five CT features were included in the score model, including tumor size (4 points), ill-defined margin (6 points), intratumoral enlarged vessels (5 points), heterogeneous enhancement pattern (4 points), and exophytic or mixed growth pattern (2 points). Then, based on the calibration results, performance was merely assessed as very low and high* risk. The AUCs of the score model for very low risk and high* risk were 0.973 and 0.977, and the cutoff points were 3 points (97.30%, 93.81%) and 7 points (92.19%, 94.19%), respectively. In the validation cohort, the AUCs were 0.912 and 0.972, and the cutoff values were 3 points (92.31%, 85.42%) and 5 points (100%, 87.88%), respectively. The model was stratified into 3 ranges: 0-3 points for very low risk, 4-8 points for low risk, and 9-21 points for high* risk. A concise and practical score system for gastric GISTs risk stratification was proposed.

Tyrosine kinase inhibitors for solid tumors in the past 20 years (2001-2020)

Tyrosine kinases are implicated in tumorigenesis and progression, and have emerged as major targets for drug discovery. Tyrosine kinase inhibitors (TKIs) inhibit corresponding kinases from phosphorylating tyrosine residues of their substrates and then block the activation of downstream signaling pathways. Over the past 20 years, multiple robust and well-tolerated TKIs with single or multiple targets including EGFR, ALK, ROS1, HER2, NTRK, VEGFR, RET, MET, MEK, FGFR, PDGFR, and KIT have been developed, contributing to the realization of precision cancer medicine based on individual patient's genetic alteration features. TKIs have dramatically improved patients' survival and quality of life, and shifted treatment paradigm of various solid tumors. In this article, we summarized the developing history of TKIs for treatment of solid tumors, aiming to provide up-to-date evidence for clinical decision-making and insight for future studies.

ADAM-Mediated Signalling Pathways in Gastrointestinal Cancer Formation

Tumour growth is not solely driven by tumour cell-intrinsic mechanisms, but also depends on paracrine signals provided by the tumour micro-environment. These signals comprise cytokines and growth factors that are synthesized as trans-membrane proteins and need to be liberated by limited proteolysis also termed ectodomain shedding. Members of the family of A disintegrin and metalloproteases (ADAM) are major mediators of ectodomain shedding and therefore initiators of paracrine signal transduction. In this review, we summarize the current knowledge on how ADAM proteases on tumour cells but also on cells of the tumour micro-environment contribute to the formation of gastrointestinal tumours, and discuss how these processes can be exploited pharmacologically.

Frequent KIT mutations in skin lesions of patients with BRAF wild-type Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is characterized by mutations of the RAS-RAF-MAPK signaling pathway. We analyzed MAP2K1, NRAS and KIT mutation incidence in skin lesions of BRAF wild-type (wt) LCH patients. We evaluated the occurrence of MAP2K1, NRAS and KIT mutations in seven LCH and one indeterminate cell histiocytosis (ICH) patients. MAP2K1 mutation frequency was found to be 3/7 (42.9%) in LCH and also found in ICH. Similarly, the KIT mutation frequency was found to be equally prevalent (4/7, 57.1%) in LCH and also occurred in ICH. Involvement of KIT exons in LCH-ICH indicated that exon 9/11/18 were equally prevalent followed by exon 13. This exploratory analysis on BRAF-wt LCH revealed a KIT mutation rate comparable to MAP2K1. Although the detected KIT mutations are different from activating mutations found in other KIT-dependent neoplasms, our data suggest that KIT-inhibitors might have a role in treating BRAF-wt LCH patients.

Small molecule tyrosine kinase inhibitors in glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor, with poor survival despite treatment with surgery, radiotherapy, and chemotherapy with temozolomide. Little progress has been made over the last two decades, and there remain unmet medical needs. Approximately 45% of patients with GBM carry EGFR mutations, and 13% of them possess altered PDGFR genes. Moreover, VEGF/VEGFR mutations are also observed in the patient population. Tyrosine kinase inhibitors (TKIs) are emerging cancer therapy drugs that inhibit signal transduction cascades affecting cell proliferation, migration, and angiogenesis. Indications for small molecule TKIs have been successfully expanded to multiple types of cancer; however, none of the TKIs have been approved for patients with GBM. In this review, we summarize clinical trials of small molecule TKIs in patients with GBM and plausible hypotheses for negative clinical study results. We also discuss the potential TKI candidates that presented significant preclinical outcomes in patients with GBM.

Imatinib in combination with phosphoinositol kinase inhibitor buparlisib in patients with gastrointestinal stromal tumour who failed prior therapy with imatinib and sunitinib: a Phase 1b, multicentre study

Background

The majority of patients with advanced gastrointestinal stromal tumours (GISTs) develop resistance to imatinib and sunitinib, the standard of care for these patients. This study evaluated the combination of buparlisib, an oral phosphoinositide 3-kinase (PI3K) inhibitor, with imatinib in patients with advanced GIST, who have failed prior therapy with imatinib and sunitinib.

Methods

This Phase 1b, multicentre, open-label study aimed to determine the maximum tolerated dose (MTD) and/or a recommended Phase 2 dose of buparlisib in combination with 400 mg of imatinib through a dose-escalation part and a dose-expansion part, and also evaluated the clinical profile of the combination.

Results

Sixty patients were enrolled, including 25 in the dose-escalation part and 35 in the dose-expansion part. In the combination, MTD of buparlisib was established as 80 mg. No partial or complete responses were observed. The estimated median progression-free survival was 3.5 months in the expansion phase. Overall, 98.3% of patients had treatment-related adverse events (AEs), including 45% with grade 3 or 4 AEs.

Conclusions

Buparlisib in combination with imatinib provided no additional benefit compared with currently available therapies. Due to the lack of objective responses, further development of this combination was not pursued for third-line/fourth-line advanced/metastatic GIST.

Trial registration number

NCT01468688.

Value of CT Imaging in the Differentiation of Gastric Leiomyoma From Gastric Stromal Tumor

Purpose:

To discuss significant computed tomography (CT) findings that differentiate gastric leiomyomas (GLs) from small gastric stromal tumors (GSTs).

Methods:

One hundred sixty cases with pathologically proven GLs (n = 50) and GSTs (n = 110) with comprehensive CT images were enrolled in this retrospective study. Computed tomography findings (ie, size, location, contour, growth pattern, enhancement degree, necrosis, ulceration, calcification, and lymph nodes) were analyzed through the χ2 or Fisher exact test, independent T test, and multivariate (logistic regression) analysis. Sensitivity and specificity were also calculated.

Results:

Features of cardia location, endophytic growth, homogeneous gradual enhancement, absent of necrosis, long diameter less than 24 mm, short diameter less than 20 mm, unenhanced CT value larger than 35.2 Hounsfield units (HU), portal venous phase CT value larger than 67.4 HU, and enhancement degree of arterial and venous phase less than 16.2 HU and 32.4 HU were found to be statistically significant between GLs and small GSTs ( P < .05). On multivariate analysis, cardia location, endophytic growth, and homogeneous gradual enhancement were independent predictive factors for GLs and small GSTs.

Conclusion:

These 10 CT criteria are very helpful to differentiate GLs from small GSTs. Especially cardia location, endophytic growth, and homogeneous gradual enhancement are of high value in differential diagnosis.

Current management of succinate dehydrogenase-deficient gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are increasingly recognized as having diverse biology. With the development of tyrosine kinase inhibitors molecularly matched to oncogenic KIT and PDGFRA mutations, GISTs have become a quintessential model for precision oncology. However, about 5-10% of GIST lack these driver mutations and are deficient in succinate dehydrogenase (SDH), an enzyme that converts succinate to fumarate. SDH deficiency leads to accumulation of succinate, an oncometabolite that promotes tumorigenesis. SDH-deficient GISTs are clinically unique in that they generally affect younger patients and are associated with GIST-paraganglioma hereditary syndrome, also known as Carney-Stratakis Syndrome. SDH-deficient GISTs are generally resistant to tyrosine-kinase inhibitors, the standard treatment for advanced or metastatic GIST. Thus, surgical resection is the mainstay of treatment for localized disease, but recurrence is common. Clinical trials are currently underway investigating systemic agents for treatment of advanced SDH-deficient GIST. However, further studies are warranted to improve our understanding of SDH-deficient GIST disease biology, natural history, surgical approaches, and novel therapeutics.

Comprehensive review into the challenges of gastrointestinal tumors in the Gulf and Levant countries

Although gastrointestinal stromal tumors (GISTs) are rare, with an incidence of 1/100000 per year, they are the most common sarcomas in the peritoneal cavity. Despite considerable progress in the diagnosis and treatment of GIST, about half of all patients are estimated to experience recurrence. With only two drugs, sunitinib and regorafenib, approved by the Food and Drug Administration, selecting treatment options after imatinib failure and coordinating multidisciplinary care remain challenging. In addition, physicians across the Middle East face some additional and unique challenges such as lack of published local data from clinical trials, national disease registries and regional scientific research, limited access to treatment, lack of standardization of care, and limited access to mutational analysis. Although global guidelines set a framework for the management of GIST, there are no standard local guidelines to guide clinical practice in a resource-limited environment. Therefore, a group of 11 experienced medical oncologists from across the Gulf and Levant region, part of the Rare Tumors Gastrointestinal Group, met over a period of one year to conduct a narrative review of the management of GIST and to describe regional challenges and gaps in patient management as an essential step to proposing local clinical practice recommendations.

Genetic Characterization of Molecular Targets in Korean Patients with Gastrointestinal Stromal Tumors

Purpose

Gastrointestinal stromal tumors (GISTs) frequently harbor activating gene mutations in either KIT or platelet-derived growth factor receptor A (PDGFRA) and are highly responsive to several selective tyrosine kinase inhibitors. In this study, a targeted next-generation sequencing (NGS) assay with an Oncomine Focus Assay (OFA) panel was used for the genetic characterization of molecular targets in 30 Korean patients with GIST.

Materials and Methods

Using the OFA that enables rapid and simultaneous detection of hotspots, single nucleotide variants (SNVs), insertion and deletions (Indels), copy number variants (CNVs), and gene fusions across 52 genes relevant to solid tumors, targeted NGS was performed using genomic DNA extracted from formalin-fixed and paraffin-embedded samples of 30 GISTs.

Results

Forty-three hotspot/other likely pathogenic variants (33 SNVs, 8 Indels, and 2 amplifications) in 16 genes were identified in 26 of the 30 GISTs. KIT variants were most frequent (44%, 19/43), followed by 6 variants in PIK3CA, 3 in PDGFRA, 2 each in JAK1 and EGFR, and 1 each in AKT1, ALK, CCND1, CTNNB1, FGFR3, FGFR4, GNA11, GNAQ, JAK3, MET, and SMO. Based on the mutation types, majority of the variants carried missense mutations (60%, 26/43), followed by 8 frameshifts, 6 nonsense, 1 stop-loss, and 2 amplifications.

Conclusions

Our study confirmed the advantage of using targeted NGS with a cancer gene panel to efficiently identify mutations associated with GISTs. These findings may provide a molecular genetic basis for developing new drugs targeting these gene mutations for GIST therapy.

KIT Mutation Incidence and Pattern of Melanoma in Central Europe

Data on the KIT mutation rate in melanoma in the central European region is missing. Accordingly, in a cohort of 79 BRAF/NRAS double wild type cutaneous melanoma and 17 mucosal melanoma KIT mutation was assessed by Sanger sequencing of exons 9,11,13,17 and 18. In this cutaneous melanoma cohort KIT mutation frequency was found to be 34/79 (43.04%) with a significantly higher rate in acrolentiginous melanoma (ALM) as compared to UV-induced common variants (20/34, 58.8% versus 14/45, 31.1%, p = 0.014). In the double wild type mucosal melanoma cohort the KIT mutation frequency was found to be comparable (41.2%). The actual frequency of KIT mutation in the original 227 patient cutaneous melanoma cohort was 34/227, 14.9%. Exon 11 was the most frequent mutation site (44.7%) followed by exon 9 (21.1%) equally characterizing UV-induced common histotypes and ALM tumors. In mucosal melanoma exon 9 was the most frequently involved exon followed by exon 13 and 17. KIT mutation hotspots were identified in exon 9 (c482/491/492), in exon 11 (c559,c572, c570), in exon 13 (c642), in exon 17 (c822) and in exon 18 (c853). The relatively high KIT mutation rate in cutaneous melanoma in this central-European cohort justifies regular testing of this molecular target in this entity, not only in mucosal variants.

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.

Multiple primary malignant neoplasms: A case report and literature review

Until recently, few cases of three or more malignant tumors in one patient have been reported. Owing to the high incidence rate of these tumors, the improvement in cancer diagnosis and treatment, and the extension of patient survival time, the incidence of reported multiple primary malignant neoplasms has gradually increased. The present study reported the case of a 57-year-old man with non-small cell lung cancer combined with B-Raf proto-oncogene serine/threonine kinase V600E mutation, gastrointestinal stromal tumors and lumbar vertebral malignant mucinous sarcoma. The pathogenesis, diagnosis and treatment of these three malignancies are discussed and previous studies are also reviewed. The aim of the study was to analyze the genetic mutations associated with multiple primary malignant tumors and to discuss whether those mutations with unknown functional significance could be used as therapeutic indicators. This case report will serve as a reference for future treatment of such patients.

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.

Quantitative Mass Spectrometry Imaging Reveals Mutation Status-independent Lack of Imatinib in Liver Metastases of Gastrointestinal Stromal Tumors

Mass spectrometry imaging (MSI) is an enabling technology for label-free drug disposition studies at high spatial resolution in life science- and pharmaceutical research. We present the first extensive clinical matrix-assisted laser desorption/ionization (MALDI) quantitative mass spectrometry imaging (qMSI) study of drug uptake and distribution in clinical specimen, analyzing 56 specimens of tumor and corresponding non-tumor tissues from 27 imatinib-treated patients with the biopsy-proven rare disease gastrointestinal stromal tumors (GIST). For validation, we compared MALDI-TOF-qMSI with conventional UPLC-ESI-QTOF-MS-based quantification from tissue extracts and with ultra-high resolution MALDI-FTICR-qMSI. We introduced a novel generalized nonlinear calibration model of drug quantities based on computational evaluation of drug-containing areas that enabled better data fitting and assessment of the inherent method nonlinearities. Imatinib tissue spatial maps revealed striking inefficiency in drug penetration into GIST liver metastases even though the corresponding healthy liver tissues in the vicinity showed abundant imatinib levels beyond the limit of quantification (LOQ), thus providing evidence for secondary drug resistance independent of mutation status. Taken together, these findings underscore the important application of MALDI-qMSI in studying the spatial distribution of molecularly targeted therapeutics in oncology, namely to serve as orthogonal post-surgical approach to evaluate the contribution of anticancer drug disposition to resistance against treatment.

Effect of the imatinib treatment regimen on the postoperative prognosis of patients with high-risk gastrointestinal stromal tumors

Background: Surgical resection is the standard treatment for localized and potentially resectable gastrointestinal stromal tumors (GISTs), If the postoperative pathology diagnosis indicates that patients are at high risk of recurrence, they should be treated with imatinib. Even though the introduction of imatinib substantially improved the outcome of GIST patients, it is unclear whether different imatinib treatment regimens affect patients' survival. Methods: This retrospective study included 120 patients who underwent tumor resection for high-risk GISTs between January 2009 and October 2018. The patients were divided into three groups: one group of patients received postoperative imatinib adjuvant therapy regularly (regular treatment group); the second group was not treated with imatinib until they were found to have disease progression (observation group); the third group was treated with postoperative imatinib adjuvant therapy irregularly (irregularly treatment group). The progression-free survival (PFS) and overall survival (OS) were compared between the three groups, and the prognostic risk factors were analysed by the Cox regression model. Results: The median PFS was 45 months (range: 25-59). The 3- and 5-year PFS values were 71.3% and 49.9%, respectively. The PFS in the regular group was longer than in the observation group and irregular group (P<0.001). The median OS was 59 months (range:47-78). The 3- and 5-year OS values were 91.6% and 84.2%, respectively. There were no differences in OS among the three groups (P=0.150). The extent of radical resection (P<0.001) and intraoperative tumor rupture (P=0.005) were independent prognostic factors influencing OS. Conclusions: Irregular administration of imatinib was associated with a worse PFS, but it did not affect the OS of patients with high-risk GISTs. Avoiding intraoperative tumor rupture and R0 resection were associated with better survival.