Molecular biomarkers for prognosis of gastrointestinal stromal tumor

Glycolysis in gastrointestinal stromal tumor: a brief overview

Gastrointestinal stromal tumor (GIST) is the most prevalent mesenchymal tumor of the digestive tract. Its growth is primarily influenced by mutations in KIT or PDGFRA. Surgery is the primary treatment option for GIST; however, KIT inhibitors, such as imatinib, are used for inoperable cases. Resistance to imatinib is an upcoming challenge, especially because the effectiveness of alternative drugs is limited. Enhancement of the glycolysis pathway in cancer cells has been identified as a key feature in cancer. This unique metabolic activity has implications on tumor growth, prognosis, and resistance to therapy, even in GIST. Members of the glucose transporter (GLUT) family (particularly GLUT-1) play a significant role in GIST progression and response to treatment. Diagnostic imaging using 18F-fluorodeoxyglucose positron emission tomography/computed tomography, which enables visualization of glucose metabolism, can aid in GIST diagnosis and risk assessment. The interplay between glycolysis and GIST can lead to the development of various therapeutic strategies, especially those involving glycolysis-related molecules, such as hexokinase and lactate dehydrogenase. However, further research is required to understand the full spectrum of glycolysis in GIST and its therapeutic potential. Herein, we present an exhaustive overview and analysis of the role of glycolysis in GIST, especially as a therapeutic target.

Prediction of Ki-67 expression in gastrointestinal stromal tumors using radiomics of plain and multiphase contrast-enhanced CT

OBJECTIVE

To study the value of radiomics models based on plain and multiphase contrast-enhanced CT to predict Ki-67 expression in gastrointestinal stromal tumors (GISTs).

METHODS

A total of 215 patients with GISTs were retrospectively analyzed, including 150 patients in one hospital as the training set and 65 patients in another hospital as the external verification set. The tumor at the largest level of CT images was delineated as the region of interest (ROI). The maximum diameter of the ROI was defined as the tumor size. A total of 851 radiomics features were extracted from each ROI by 3D Slicer Radiomics. After dimensionality reduction, three machine learning classification algorithms including logistic regression (LR), random forest (RF), and support vector machine (SVM) were used for Ki-67 expression prediction. Using a multivariable logistic model, a nomogram was established to predict the expression of Ki-67 individually.

RESULTS

Delong tests showed that the SVM models had the highest accuracy in the arterial phase (Z value 0.217-1.139) and venous phase (Z value 0.022-1.396). For the plain phase, LR and SVM models had the highest accuracy (Z value 0.874-1.824, 1.139-1.763). For the delayed phase, LR models had the highest accuracy (Z value 0.056-1.824). For the combined phase, RF models had the highest accuracy (Z value 0.232-1.978). There was no significant difference among the above models for KI-67 expression prediction (Z value 0.022-1.978). A nomogram was developed with a C-index of 0.913 (95% CI, 0.878 to 0.956).

CONCLUSIONS

Radiomics of both plain and enhanced CT images could accurately predict the expression of Ki-67 in GIST. For patients who were not suitable to use contrast agents, plain scan could be used as an alternative.

CLINICAL RELEVANCE STATEMENT

CT radiomics could accurately predict the expression of Ki-67 in GIST, which has a great clinical value in reflecting the proliferative activity of tumor cells and helping determine whether a patient is suitable for adjuvant therapy with imatinib.

KEY POINTS

• Radiomics of both plain and enhanced CT images could accurately predict the expression of Ki-67 in GIST. • For patients who were not suitable to use contrast agents, plain scan could be used as an alternative. • A radiomics nomogram was developed to allow personalized preoperative evaluation with high accuracy.

A New Online Dynamic Nomogram: Construction and Validation of a Predictive Model for Distant Metastasis Risk and Prognosis in Patients with Gastrointestinal Stromal Tumors

BACKGROUND

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the digestive tract, among which patients with distant metastases tend to have a poor prognosis. This study aimed to develop a model for predicting distant metastasis in GIST patients and to develop two models for monitoring overall survival (OS) and cancer-specific survival (CSS) in GIST patients with metastasis. This would allow us to develop an optimal, individualized treatment strategy.

METHODS

We reviewed demographic and clinicopathological characteristics data from 2010 to 2017 of patients diagnosed with GIST in the Surveillance, Epidemiology, and End Results (SEER) database. The data of the external validation group was reviewed from the Forth Hospital of Hebei Medical University. Univariate and multivariate logistic regression analyses were used to confirm the independent risk factors for distant metastasis in the GIST patients, and univariate and multivariate Cox regression analyses were performed to identify the independent prognostic factors for OS and CSS in the GIST patients with distant metastasis. Subsequently, three web-based novel nomograms were developed, which were evaluated by the receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

Of the 3639 patients who met the inclusion criteria, 418 (11.4%) had distant metastases. The risk factors for distant metastasis in GIST patients included sex, primary site, grade, N stage, tumor size, and mitotic count. For OS, the independent prognosis factors for GIST patients with metastasis included age, race, marital, primary site, chemotherapy, mitotic count, and metastasis at the lung, and for CSS, age, race, marital, primary site, and metastasis at the lung were the independent prognosis factors. Three web-based nomograms were constructed based on these independent factors, respectively. The ROC curves, calibration curves, and DCA were performed in the training, testing, and validation sets which confirmed the high accuracy and strong clinical practice power for the nomograms.

CONCLUSION

Population-based nomograms can help clinicians predict the occurrence and prognosis of distant metastases in patients with GIST, which may be helpful for clinicians to formulate clinical management and appropriate treatment strategies.

Tumor-associated macrophages mediate gastrointestinal stromal tumor cell metastasis through CXCL2/CXCR2

BACKGROUND

Tumor-associated macrophages (TAMs) are linked with the progression and poor prognosis of multifarious solid tumors, but the regulatory mechanisms involved in gastrointestinal stromal tumors (GIST) remain indistinct. This study intended to delve into the job of TAM-derived chemokines in promoting metastasis in GIST microenvironment.

METHODS

Expression levels of M2-TAM markers and CXCL2 in primary and metastatic tissues of GIST were analyzed by bioinformatics methods, and we analyzed the correlation between CXCL2 and M2-TAM markers. Immunofluorescence was applied to assay CXCL2 and M2-TAM marker protein (CD68 and CD206) expression in tumor tissues. Serum CXCL2 concentration in metastatic and non-metastatic patients was assayed by ELISA. The differentiation of THP-1 cells was tested by flow cytometry. Cell function test was utilized to analyze the viability, invasion and migration of GIST cells. Western blot was used to examine the expression of epithelial-mesenchymal transition (EMT)-related proteins. The mouse liver metastasis model was established, and the effects of CXCL2 and EMT-related genes on metastasis were confirmed by hematoxylin-eosin staining and immunohistochemistry experiments.

RESULTS

Bioinformatics analysis ascertained that M2-TAM marker proteins and chemokine CXCL2 were highly expressed in GIST metastatic tissues, and CXCL2 and TAM were co-located in tumor tissues. Results of in vitro cell function experiments displayed that CXCL2 secreted by M2-TAM promoted the invasion, migration and EMT of GIST tumor cells, and the anti-CXCL2 antibody could block the metastasis promoting effect of CXCL2. Additionally, the silencing of CXCR2 in GIST cells inhibited the metastasis promoting effect of CXCL2. Animal studies further confirmed that CXCL2 promoted liver metastasis of GIST in vivo.

CONCLUSION

This study preliminarily revealed the mechanism of M2-TAM promoting tumor metastasis by secreting CXCL2 in GIST tumor microenvironment, and proffered theoretical reference for the development of immunotherapy strategies targeting M2-TAM.

Exploring the Dynamic Crosstalk between the Immune System and Genetics in Gastrointestinal Stromal Tumors

Gastrointestinal Stromal Tumors (GISTs) represent a paradigmatic model of oncogene addiction. Despite the well-known impact of the mutational status on clinical outcomes, we need to expand our knowledge to other factors that influence behavior heterogeneity in GIST patients. A growing body of studies has revealed that the tumor microenvironment (TME), mostly populated by tumor-associated macrophages (TAMs) and lymphocytes (TILs), and stromal differentiation (SD) have a significant impact on prognosis and response to treatment. Interestingly, even though the current knowledge of the role of immune response in this setting is still limited, recent pre-clinical and clinical data have highlighted the relevance of the TME in GISTs, with possible implications for clinical practice in the near future. Moreover, the expression of immune checkpoints, such as PD-L1, PD-1, and CTLA-4, and their relationship to the clinical phenotype in GIST are emerging as potential prognostic biomarkers. Looking forward, these variables related to the underlying tumoral microenvironment in GIST, though limited to still-ongoing trials, might lead to the potential use of immunotherapy, alone or in combination with targeted therapy, in advanced TKI-refractory GISTs. This review aims to deepen understanding of the potential link between mutational status and the immune microenvironment in GIST.

Refining Prognosis in Localized Gastrointestinal Stromal Tumor: Clinical Significance of Phosphatase and Tensin Homolog Low Expression and Gene Loss

To investigate the use of PTEN biomarker to improve prognostic stratification in patients with localized gastrointestinal stromal tumor (GIST).

Potential Value of Circular RNA circTBC1D4 in Gastrointestinal Stromal Tumors

Aims

To explore the expression of circular RNA (circRNA) in gastrointestinal stromal tumors.

Background

Gastrointestinal stromal tumors (GIST) are mainly distributed in the stomach and small intestine. Recently, it has been verified that circular RNA (circRNA) has an important function in the regulation of GIST. Nevertheless, detailed investigations of circRNA-miRNA-mRNA regulatory networks in GIST are lacking.

Objective

To analyze the gastrointestinal stromal tumor circRNA-miRNA-mRNA network, assessing the effect of circle RNA in gastrointestinal stromal tumors.

Method

All the differential circRNAs and mRNAs were obtained from Gene Expression Omnibus (GEO) microarray data (GSE131481 and GSE147303, GSE131481, and GSE13861). Furthermore, a circRNA-miRNA-mRNA network was established. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were used to reveal the correlation between the functions of signaling pathways and target genes. The hub genes of protein-protein interaction (PPI) network and cytoHubba were also defined. Quantitative real-time PCR (qRT-PCR) was used to measure the expression levels of hsa-circ-0002917 (circTBC1D4), hsa-miR-590-5p (miR-590-5p), and PLN.

Results

PPI network and Cytoscape showed that ATP1A2, PLN, KCNMA1, and SCNN1B were four central DEGs. GO analysis results revealed that DEGs were involved in negative management of myocardial contraction, regulation of myocardial cell contraction, ethanol oxidation, cellular potassium ion homeostasis, and relaxation of cardiac muscle, and KEGG analysis showed that major DEGs were with cGMP-PKG signaling pathway. Moreover, we obtained two pairs of axes, namely, hsa-circ-0039216/hsa-miR-338-3p/ATP1A2 and hsa-circ-0002917/hsa-miR-590-5p/PLN. The target of TBC1D4 is miR-590-5p, and miR-590-5p increased after knocking down TBC1D4. Moreover, PLN was the target of miR-590-5p, and miR-590-5p exerts antitumor effects by reducing PLN.

Conclusions

In this study, we constructed a circRNA-miRNA-mRNA management network interrelated with GIST and researched the potential roles of circRNA. Moreover, we discovered a new molecular landmarker for the prediction, diagnosis, and therapy of patients.

Detection of cancer biomarkers CA125 and CA199 via terahertz metasurface immunosensor

The cancer biomarkers including AFP, CEA, CA199 and CA125, are of great importance in the diagnosis, prognostic prediction and recurrence monitoring of malignancies. However, in clinical practical applications, most tumor cancer biomarkers are lack of sensitivity and specificity. In this study, we propose a terahertz (THz) metasurface (MS) immunosensor coupled with gold nanoparticles (AuNPs), which have good biocompatibility and high specific surface area for biomarkers. Firstly, we added AuNPs to the surface of the sensor. And then, the surface is modified with Anti-CA125 or Anti-CA199 to improve the sensitivity and specificity to the target antigen. The biosensor was fabricated using a surface micromachining process and characterized by a THz-time-domain spectroscopy (TDS) system. The sensitivity of the resonance frequency of the sensor to the refractive index was 65 GHz/RIU (refractive index unit). The detection performance of the THz immunosensor was also verified with different concentrations of CA125 and CA199. The experimental results showed that the frequency shift of the resonance peak was linearly related to the concentration of CA125 and CA199. The detection limits for both CA125 and CA199 are 0.01 U/ml, which is better than that of other common methods. Finally, serum samples were collected and detected to explore whether this method is suitable for clinical detection. The results are consistent with the results of antigen recognition. This study proves that the practicability of the THz immunosensor, which potentially provides important techniques and equipment for improving the sensitivity and specificity of cancer biomarkers.

A Case Report of Multiple Gastrointestinal Stromal Tumors: Imaging Findings, Surgical Approach, and Review of the Literature

Introduction

Multiple gastrointestinal stromal tumors (GISTs) are rare tumors. Differential diagnosis between metastatic and multiple GISTs represents a challenge for a proper workup, prediction prognosis, and therapeutic strategy.

Case presentation

We present the case of 67-year-old man with computed tomography (CT) evidence of multiple exophytic lesions in the abdomen, reaching diameters ranging from 1 to 9 cm, without any signs of organs infiltration, and resulting positive at 18F-FDG-PET/CT. Laparoscopic biopsy revealed multiple GISTs, and surgical resection by using an open approach was performed to achieve radicality. Moreover, an extensive review of the current literature was performed.

Results

Small GISTs (<5 cm) can be treated by the laparoscopic approach, while in the case of large GISTs (>5 cm), tumor location and size should be taken into account to reach the stage of radical surgery avoiding tumor rupture. For metastatic GISTs, Imatinib represents the first choice of treatment, and surgery should be considered only in a few selected cases when all lesions are resectable.

Conclusion

Sporadic multiple GISTs are a rare event, imaging findings are not specific for GISTs, and biopsy requires a secure diagnosis and proper management. In the case of large lesions, with a high risk of vessels injury, laparotomy excision should be considered to achieve radicality and to avoid tumor rupture.

Circulating Tumor DNA Mutations in Progressive Gastrointestinal Stromal Tumors Identify Biomarkers of Treatment Resistance and Uncover Potential Therapeutic Strategies

Liquid biopsy circulating tumor DNA (ctDNA)-based approaches may represent a non-invasive means for molecular interrogation of gastrointestinal stromal tumors (GISTs). We deployed a customized 29-gene Archer^® LiquidPlex™ targeted panel on 64 plasma samples from 46 patients. The majority were known to harbor KIT mutations (n = 41, 89.1%), while 3 were PDGFRA exon 18 D842V mutants and the rest (n = 2) were wild type for KIT and PDGFRA. In terms of disease stage, 14 (30.4%) were localized GISTs that had undergone complete surgical resection while the rest (n = 32) were metastatic. Among ten patients, including 7 on tyrosine kinase inhibitors, with evidence of disease progression at study inclusion, mutations in ctDNA were detected in 7 cases (70%). Known somatic mutations in KIT (n = 5) or PDGFRA (n = 1) in ctDNA were identified only among 6 of the 10 patients. These KIT mutants included duplication, indels, and single-nucleotide variants. The median mutant AF in ctDNA was 11.0% (range, 0.38%–45.0%). In patients with metastatic progressive KIT-mutant GIST, tumor burden was higher with detectable KIT ctDNA mutation than in those without (median, 5.97 cm vs. 2.40 cm, p = 0.0195). None of the known tumor mutations were detected in ctDNA for localized cases (n = 14) or metastatic cases without evidence of disease progression (n = 22). In patients with serial samples along progression of disease, secondary acquired mutations, including a potentially actionable PIK3CA exon 9 c.1633G>A mutation, were detected. ctDNA mutations were not detectable when patients responded to a switch in TKI therapy. In conclusion, detection of GIST-related mutations in ctDNA using a customized targeted NGS panel represents an attractive non-invasive means to obtain clinically tractable information at the time of disease progression.

[Gastrointestinal stromal tumors: potential of minimally invasive surgical interventions]

OBJECTIVE

To analyze the issue of gastrointestinal stromal tumors (GISTs) and potential of minimally invasive surgical interventions.

MATERIAL AND METHODS

We analyzed postoperative outcomes in 97 patients with gastric and intestinal GISTs who underwent surgical treatment at the National Medical Research Centre for Oncology between 2015 and 2020.

RESULTS

Twenty (24.7) patients with gastric GISTs underwent laparoscopic partial and distal gastric resections. Five (35.7%) patients with GISTs of the small intestine underwent minimally invasive segmental bowel resections. Only minimally invasive interventions were performed in patients with rectal GISTs. Analysis of laparoscopic and open surgeries for GISTs found no significant differences. Analysis of laparoscopic and open surgeries for gastric and small bowel GISTs revealed the obvious advantages of minimally invasive access regarding postoperative outcomes. Indeed, we found no need for nasogastric drainage in 50% of patients (p<0.001), earlier recovery of intestinal motility and oral feeding (p<0.001), lower postoperative morbidity (p=0.036), fast recovery of motor activity (p<0.001) and shorter postoperative hospital-stay (p<0.001).

CONCLUSION

Despite small incidence, GISTs are a complex problem in modern oncology. Diagnosis and treatment require a multidisciplinary medical team (morphologists, geneticists, radiologists, surgeons, chemotherapists, gastroenterologists and other specialists) that is possible in a reference center. Minimally invasive interventions for GISTs of the stomach, small intestine and rectum improve postoperative course.

Caveolin-1 expression predicts favourable outcome and correlates with PDGFRA mutations in gastrointestinal stromal tumours (GISTs)

AIMS

Novel prognostic markers are warranted for gastrointestinal stromal tumours. Caveolin-1 is a multifunctional protein that proved to be associated with outcome in multiple tumour types. Aim of this study was to investigate Caveolin-1 expression and prognostic efficacy in a series of gastrointestinal stromal tumours.

METHODS

Caveolin-1 expression was assessed by immunohistochemistry in a retrospective series of 66 gastrointestinal stromal tumours representative of the different molecular subtypes. Correlations with clinical, histopathological and molecular features were investigated. Statistical analyses were performed as appropriate.

RESULTS

Thirty-five cases out of 66 (53.0%) expressed Caveolin-1. Presence of Caveolin-1 expression correlated with favourable histopathologic and clinical traits, including a lower mitotic count (p=0.003) and lower relapse rate (p=0.005). Caveolin-1 expression also resulted associated with the presence of PDGFRA mutations (p=0.010). Outcome analyses showed a favourable prognostic significance of Caveolin-1 expression in terms of relapse-free survival (HR=0.14; 95% CI=0.03 to 0.63) and overall survival (HR=0.29; 95% CI=0.11 to 0.74), even after adjusting for the mutational subgroup (relapse-free survival: HR=0.14, 95% CI=0.04 to 0.44; overall survival: HR=0.29, 95% CI=0.11 to 0.51) and imatinib treatment (relapse-free survival: HR=0.14, 95% CI=0.02 to 0.81; overall survival: HR=0.29, 95% CI=0.17 to 0.48).

CONCLUSION

Caveolin-1 represents a novel prognostic marker in gastrointestinal stromal tumours. Further studies are warranted to validate these results and to explore the mechanisms linking Caveolin-1 expression with the PDGFRA oncogenic pathway.

Frequency of Plexiform Fibromyxoma relative to gastrointestinal stromal tumor: A single center study

Plexiform Fibromyxoma (PF) is an exceedingly rare mesenchymal tumor of the gastric antrum that was first described in 2007. PF is a close mimic of gastrointestinal stromal tumor (GIST) clinically and histopathologically, but the frequency of PF relative to GIST is unknown. Moreover, although likely benign, long-term follow-up of PF is limited due to its recent description and rarity. PF has not been reported in distal jejunum. 118 primary GISTs that were surgically resected at our center (2000-2019) were retrieved. The patients' age, gender, clinical presentation, tumor location, size and number, and the presence or absence of metastasis, were documented. Risk of progressive disease was assessed according to the published GIST risk stratification model. Two unique cases of PF were compared. One gastric PF has been followed-up for 8 years, and the other occurred in the distal jejunum. In the latter, the PF diagnosis was rendered after the case was re-reviewed for the study. Clinical presentation resembled GIST in both PF cases. 14% of GISTs showed high risk features or were clinically malignant, whereas the PF patient with 8-year follow-up was free of disease. Based on this study, PF may be under-recognized, with 1 to 2% (1.7%) of GIST-like tumors possibly representing PF. PF may involve variable segments of intestine similar to GIST. Given the remarkable clinical and histopathologic overlap with GIST but differing outcomes, awareness and cognizance of this rare entity, plexiform fibromyxoma, is required for proper patient care.

Prognostic Indicators for Gastrointestinal Stromal Tumors: A Review

Gastrointestinal stromal tumors (GISTs) are potentially malignancies that can occur anywhere in the digestive tract. Tyrosine kinase inhibitors (TKIs) such as imatinib have proven effective since the discovery of KIT and PDGFRA. The current version of NCNN, ESMO and EURACAN guidelines recognized that the three main prognostic factors are the mitotic rate, tumor size and tumor site. In addition, tumor rupture is also recognized as an independent risk factor. However, recent evidence shows that various types of gene mutations are associated with prognosis, and influencing factors such as gastrointestinal bleeding and high Ki67 index have been associated with poor prognosis. It shows that the current risk classification is still insufficient and controversial. With the emergence of more and more lack mutation in KIT/PDGFRA GISTs (KIT/PDGFRA wild-type GISTs) or drug resistance genes, primary and secondary drug resistance problems are caused, which makes the treatment of late or metastatic GIST face challenges. Therefore, this article will review the clinicopathological characteristics of GIST, the special molecular subtypes and other factors that may affect prognosis. We will also explore reliable prognostic markers for better postoperative management and improve the prognosis of patients with GIST.

Progress in determining response to treatment in gastrointestinal stromal tumor

Introduction: Gastrointestinal stromal tumor (GIST) is the most common malignant mesenchymal tumor of the gastrointestinal system. Multiple advances in the management of GIST from the discovery of KIT/PDGRA and other genetic alterations have led to the development of multiple tyrosine kinase inhibitors. Response assessment in GIST is determined with iRECIST (Response Evaluation Criteria in Solid Tumors), PERCIST (PET response criteria in solid tumors), or Choi criteria. Molecular genotyping of the tissue samples is the recent standard for diagnosis, treatment, and response to treatment.Areas covered: In this study, we provide a brief overview of the history of the GIST, molecular sequencing, available treatment options and clinical trials, radiologic response assessment, and the role of ctDNA in response evaluation.Expert opinion: Future GIST management is related to the development of sensitive assays to detect genetic alterations for initial diagnosis, treatment selection, monitoring the response to treatment, resistant mutations, and predicting survival.

Histone methyltransferase SETD2: a potential tumor suppressor in solid cancers

Epigenetic regulation plays an important role in the occurrence, development and treatment of malignant tumors; and a great deal of attention has been paid to the histone methylation level in recent years. As a 230-kD epigenetic regulator, the histone H3 lysine 36 histone (H3K36) methyltransferase SETD2 is a key enzyme of the nuclear receptor SET domain-containing (NSD) family, which is associated with a specific hyperphosphorylated domain, a large subunit of RNA polymerase II (RNAPII), named RNAPII subunit B1 (RPB1), and SETD2 which methylates the ly-36 position of dimethylated histone H3 (H3K36me2) to generate trimethylated H3K36 (H3K36me3). SETD2 is involved in various cellular processes, including transcriptional regulation, DNA damage repair, non-histone protein-related functions and some other processes. Great efforts of high-throughput sequencing have revealed that SETD2 is mutated or its function is lost in a range of solid cancers, including renal cancer, gastrointestinal cancer, lung cancer, pancreatic cancer, osteosarcoma, and so on. Mutation, or functional loss, of the SETD2 gene produces dysfunction in corresponding tumor tissue proteins, leading to tumorigenesis, progression, chemotherapy resistance, and unfavorable prognosis, suggesting that SETD2 possibly acts as a tumor suppressor. However, its underlying mechanism remains largely unexplored. In the present study, we summarized the latest advances of effects of SETD2 expression at the mRNA and protein levels in solid cancers, and its potential molecular and cellular functions as well as clinical applications were also reviewed.

Signatures of circulating microRNA in four sarcoma subtypes

Background: Sarcomas are rare malignant tumors of mesenchymal origin. The discovery of circulating biomarkers with high diagnostic value could supplement diagnosis of this heterogenous group of tumors. The aim of this study was to identify the profiles of circulating miRNA (c-miRNAs) in four groups of common bone and soft tissue sarcomas.

Methods: At the time of diagnosis, blood samples were collected from 86 patients: 36 with locally advanced/unresectable/metastatic gastrointestinal stromal tumor (GIST) who received first-line treatment with imatinib; 16 with locally advanced osteosarcoma (OS); 26 with locally advanced synovial sarcoma (SS); and eight with locally advanced Ewing sarcoma (ES). In addition, samples were collected from 30 healthy controls. C-miRNAs were isolated using a miRCURY RNA Isolation Kit, followed by preparation of cDNA libraries and sequencing on the Ion Proton platform.

Results: Pair-wise comparisons identified 156 unique c-miRNAs (adjusted P-value < 0.05) showing significant dysregulation between controls and patients; of these, 24, 36, 42, and 99 differentiated controls from pretherapeutic OS, SS, ES, and GIST, respectively. Ten c-miRNAs were commonly altered in at least three sarcoma types. Receiver operating characteristic curves and area under the curve (ROC-AUC) analyses revealed that a four-miRNA diagnostic classifier was able to differentiate controls from ES, GIST, OS, and SS, with AUC-ROC values of 1, 0.97, 0.95, and 0.94, respectively.

Conclusions: Aberrant miRNA expression signatures were identified in serum from patients with four different sarcoma subtypes. Differences in miRNA expression profiles between sarcoma patients and healthy volunteers suggest that miRNAs may play a role in sarcoma development.

A Population-Based Study of the Incidence and Survival of Anorectal Gastrointestinal Stromal Tumor

Background

Gastrointestinal stromal tumor (GIST) is the most common type of primary gastrointestinal mesenchymal tumor, but GISTs arising in the anus and rectum are rare. This study aimed to undertake a population-based analysis of the incidence, patient demographics, and survival of patients with anorectal GIST compared with patients with GIST arising from other sites based on the Surveillance, Epidemiology, and End Results (SEER) Program database.

Material/Methods

The SEER database was used to identify all patients diagnosed with GIST and patients diagnosed with anorectal GIST from 2000 to 2015. The incidence of GIST, baseline clinical and demographic data, tumor stage, and patient survival data were analyzed, including overall survival (OS) and cancer-specific survival (CSS).

Results

A total of 277 patients with anorectal GIST were identified, with an incidence of 0.018 per 100,000. The incidence of GIST arising from other sites was 0.719 per 100,000. The median age at diagnosis for anorectal GIST was 57.5 years (range, 26–92 years), median tumor size was 6.55 cm (range, 0.6–20 cm), and surgery, but not chemotherapy, improved OS and CSS. Patients with anorectal GIST had a mean 1-year, 3-year, 5-year, and 10-year OS of 91.1%, 82.5%, 75.2%, and 58.5%, respectively. Patients with GIST arising at other sites had a mean 1-year, 3-year, 5-year, and 10-year OS of 88.3%, 76.4%, 66.5%, and 46.8%, respectively.

Conclusions

Anorectal GIST is a rare tumor that has a better outcome compared with GISTs arising at other sites in the gastrointestinal tract.