Potential Of Gastrointestinal Stromal Tumors Research Articles

Use of a Convolutional Neural Network to Predict the Malignant Potential of Gastrointestinal Stromal Tumors in Transabdominal Ultrasound Images: Visualization of the Focus of the Prediction Model

We established a deep convolutional neural network (CNN) model based on ultrasound images (US-CNN) for predicting the malignant potential of gastrointestinal stromal tumors (GISTs). A total of 980 ultrasound images from 245 pathology-confirmed GIST patients after surgical operation were retrospectively collected and divided into a low (very-low-risk, low-risk) and a high (medium-risk, high-risk) malignant potential group. Eight pre-trained CNN models were used to extract the features. The CNN model with the highest accuracy in the test set was selected. The model's performance was evaluated by calculating accuracy, sensitivity, specificity, positive-predictive value (PPV), negative-predictive value (NPV) and the F1 score. Three radiologists with different experience levels also predicted the malignant potential of GISTs in the same test set. US-CNN and human assessments were compared. Subsequently, gradient-weighted class activation diagrams (Grad-CAMs) were used to visualize the model's final classification decisions. Among the eight transfer learning-based CNNs, ResNet18 performed best. The accuracy, sensitivity, specificity, PPV, NPV and F1 score were 0.88, 0.86, 0.89, 0.82, 0.92 and 0.90, respectively, which were significantly better than those achieved by radiologists (resident doctor: 0.66, 0.55, 0.79, 0.74, 0.62 and 0.69; attending doctor: 0.68, 0.59, 0.78, 0.70, 0.69 and 0.73; professor: 0.69, 0.63, 0.72, 0.51, 0.80 and 0.76). Model interpretation with Grad-CAMs revealed that the activated areas mainly focused on cystic necrosis and margins. The US-CNN model predicts GIST malignant potential well, which can assist in clinical treatment decision-making.

Artificial intelligence in endoscopic ultrasonography: risk stratification of gastric gastrointestinal stromal tumors.

Previous studies have identified useful endoscopic ultrasonography (EUS) features to predict the malignant potential of gastrointestinal stromal tumors (GISTs). However, the results of the studies were not consistent. Artificial intelligence (AI) has shown promising results in medicine. We aimed to build a risk stratification EUS-AI model to predict the malignancy potential of GISTs. This was a retrospective study with external validation. We developed two models using EUS images from two hospitals to predict the GIST risk category. Model 1 was the four-category risk EUS-AI model, and Model 2 was the two-category risk EUS-AI model. The diagnostic performance of the models was validated with external cohorts. A total of 1320 images (880 were very low-risk, 269 were low-risk, 68 were intermediate-risk, and 103 were high-risk) were finally chosen for building the models and test sets, and a total of 656 images (211 were very low-risk, 266 were low-risk, 88 were intermediate-risk, and 91 were high-risk) were chosen for external validation. The overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the four-category risk EUS-AI model in the external validation sets by tumor were 74.50%, 55.00%, 79.05%, 53.49%, and 81.63%, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for the two-category risk EUS-AI model for the prediction of very low-risk GISTs in the external validation sets by tumor were 86.25%, 94.44%, 79.55%, 79.07%, and 94.59%, respectively. We developed a EUS-AI model for the risk stratification of GISTs with promising results, which may complement current clinical practice in the management of GISTs. The study has been registered in the Chinese Clinical Trial Registry (No. ChiCTR2100051191).

Radiomics Nomogram Based on Contrast-enhanced CT to Predict the Malignant Potential of Gastrointestinal Stromal Tumor: A Two-center Study

Contrast-enhanced computed tomography (CE-CT) was used to establish radiomics nomogram to evaluate the malignant potential of gastrointestinal stromal tumors (GISTs). A total of 500 GIST patients were enrolled in this study and divided into training cohort (n=346, our center) and validation cohort (n=154, another center). Minimum redundancy maximum relevance (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithms were used to select the feature subset with the best discriminant features from the three phases image, and five classifiers were used to establish four radiomics signatures. Preoperative radiomics nomogram was constructed by adding the clinical features determined by multivariate logistic regression analysis. The performance of radiomics signatures and nomogram were evaluated by area under the curve (AUC) of the receiver operating characteristic (ROC). The calibration of nomogram was appraised by calibration curve. A total of 13 radiomic features were extracted from tri-phase combined CE-CT images. Tri-phase combined CE-CT features+Support Vector Machine (SVM) was the bestcombination at predicting the malignant potential of GIST, with an AUC of 0.895 (95% CI 0.858-0.931) in the training cohort and 0.847 (95% CI 0.778-0.917) in the validation cohort. The nomogram also had good calibration. In the training cohort and the validation cohort, preoperative radiomics nomogram reachedAUCs of 0.927 and 0.905, respectively, which were higher than clinical. The radiomics nomogram had a good predictive effect and generalization on the malignant potential of GIST, which could effectively help guide preoperative clinical decision.

Correlation of Endoscopic Ultrasonography Features with the Mitotic Index in 2- to 5-cm Gastric Gastrointestinal Stromal Tumors

Background: Predicting the malignancy potential of gastrointestinal stromal tumor (GIST) before resection could improve patient management strategies as gastric GISTs with a low malignancy potential can be safely treated endoscopically, but surgical resection is required for those tumors with a high malignancy potential. This study aimed to evaluate endoscopic ultrasound (EUS) features of 2- to 5-cm gastric GISTs that might be used to predict their mitotic index using surgical specimens as the gold standard. Patients and Methods: Forty-nine patients (30 females and 19 males; mean age 55.1 ± 12.7 years) who underwent EUS examinations, followed by surgical resections of 2- to 5-cm gastric GISTs, were retrospectively reviewed. Results: The mean tumor size was 3.44 ± 0.97 (range 2.1–5.0) cm. A univariate analysis revealed no significant differences in age, sex, and tumor location in the low mitotic index and high mitotic index groups (all p > 0.05). In terms of EUS features, there were no significant differences in the mitotic indexes with respect to the shape, surface lobulation, border regularity, echogenicity, homogeneity, growth patterns, presence of mucosal ulceration, hyperechogenic foci, anechoic spaces, and hypoechoic halos (all p > 0.05). However, the tumor size was larger in the high mitotic index group than that in the low mitotic index group (3.97 ± 1.05 vs. 3.27 ± 0.9 cm, p = 0.03). Conclusion: Conventional EUS features are not reliable for predicting the mitotic index of 2- to 5-cm gastric GISTs. Further modalities for predicting the mitotic index are needed to prevent unnecessary surgical resections in patients with a low risk of malignancy.

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.

Special Issue No. – 10, June, 2020 Journal > Special Issue > Special Issue No. – 10, June, 2020 > Page 5 “Quantative Methods in Modern Science” organized by Academic Paper Ltd, Russia MORPHOLOGICAL AND ANATOMICAL FEATURES OF THE GENUS GAGEA SALISB., GROWING IN THE EAST KAZAKHSTAN REGION Authors: Zhamal T. Igissinova,Almash A. Kitapbayeva,Anargul S. Sharipkhanova,Alexander L. Vorobyev,Svetlana F. Kolosova,Zhanat

Special Issue No. – 10, June, 2020 Journal > Special Issue > Special Issue No. – 10, June, 2020 > Page 5 “Quantative Methods in Modern Science” organized by Academic Paper Ltd, Russia MORPHOLOGICAL AND ANATOMICAL FEATURES OF THE GENUS GAGEA SALISB., GROWING IN THE EAST KAZAKHSTAN REGION Authors: Zhamal T. Igissinova,Almash A. Kitapbayeva,Anargul S. Sharipkhanova,Alexander L. Vorobyev,Svetlana F. Kolosova,Zhanat

Contrast Enhanced Endoscopic Ultrasound Imaging for Gastrointestinal Subepithelial Tumors.

Subepithelial tumors are divided into benign subepithelial and potentially malignant gastrointestinal stromal tumors. It is difficult to distinguish between these tumor types. Contrast-enhanced harmonic endoscopic ultrasound is reportedly useful for diagnosing subepithelial tumors, can be safely and easily performed by understanding the principle and method, and can be used to distinguish between tumor types with high sensitivity on the basis of differences in contrast effect. The generated image shows a hyper-enhancement pattern in gastrointestinal stromal tumors (sensitivity, 78%–100%; specificity, 60%–100%; accuracy, 60%–100%) and hypo-enhancement pattern in benign subepithelial tumors. Contrast-enhanced harmonic endoscopic ultrasound can be used to estimate the malignancy potential of gastrointestinal stromal tumors by evaluating the uniformity of the contrast and the blood vessels inside the tumor, with abnormal intra-tumor blood vessels, heterogeneous enhancement, and non-enhancing spots suggesting malignancy. Contrast-enhanced harmonic endoscopic ultrasound has a higher sensitivity than other imaging modalities for the detection of vascularity within gastrointestinal stromal tumors. Additionally, it has been reported that treatment effects can be estimated by evaluating the blood flow in the gastrointestinal stromal tumor before and after treatment with tyrosine kinase inhibitors using contrast-enhanced ultrasound. However, there will be subjective-bias and the results depends on the performer’s skill.

Value of contrast-enhanced harmonic endoscopic ultrasonography in differentiating between gastrointestinal stromal tumors: A meta-analysis.

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is a valuable device to diagnose and determine the malignant potential of gastrointestinal stromal tumors (GIST) as early as possible when making clinical therapeutic decisions. This study aimed to estimate the ability of CH-EUS to discriminate between GIST and benign submucosal lesions (SML) and to predict their malignant potential. PubMed, MEDLINE, EMBASE, the Web of Science, and Cochrane Central Register of Controlled Trials databases were screened. Using the data provided in the literatures, 2 × 2 tables were constructed to obtain the pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. A receiver operating characteristic (ROC) curve was generated and the area under the ROC curve (AUROC) was calculated. Four studies with a total of 187 patients were identified to evaluate the value of CH-EUS in discriminating between GIST and benign SML. The pooled sensitivity, specificity, and AUROC were 89% (95% CI 0.82-0.93), 82% (95% CI 0.66-0.92), and 0.89, respectively. Five studies including 143 patients were analyzed to assess the accuracy of CH-EUS in determining the malignant potential of GIST. The pooled sensitivity, specificity, and AUROC curve of CH-EUS were 96% (95% CI 0.90-0.99), 53% (95% CI 0.40-0.66), and 0.92, respectively. CH-EUS is a safe, noninvasive method that can distinguish between GIST and benign subepithelial lesions and to predict their malignant potential to a certain extent. Large-scale, multicenter prospective studies are needed in the future.

Fractal analysis of contrast-enhanced CT images for preoperative prediction of malignant potential of gastrointestinal stromal tumor.

The purpose of this study is to assess the heterogeneity of tumor enhancement using fractal analysis on contrast-enhanced computed tomography (CE-CT) for predicting malignant potential of gastrointestinal stromal tumor (GIST). We retrospectively identified 64 patients (36M/28W; median age: 65) with GISTs who received CE-CT and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) followed by curative surgery. Fractal analysis was applied to CE-CT image, and fractal dimension (FD) was measured. Diagnostic value of FD for malignant potential of GIST was compared with that of FDG-PET using the risk classification and Ki67 index. 14 patients were categorized as the high risk, and 50 patients were as the very low, low or intermediate risk. FD of high-risk group was significantly higher than that of the other-risk group (p<0.05). The areas under the ROC curves of FD and SUVmax for prediction of high-risk group were 0.82 and 0.93 (accuracy: 84.4% and 98.5%). FD showed a significant positive correlation with Ki67 index (p=0.01). Diagnostic value of CT fractal analysis for prediction of high-risk GIST is comparable with FDG-PET. In terms of cost and availability, fractal analysis has a potential to be an optimal preoperative biomarker.

Performance of F-18 FDG PET/CT for predicting malignant potential of gastrointestinal stromal tumors: A systematic review and meta-analysis.

We aimed to explore the role of the diagnostic accuracy of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) or positron emission tomography/computed tomography (PET/CT) for prediction of malignant potential of gastrointestinal stromal tumor (GIST) through a systematic review and meta-analysis. The MEDLINE, Embase, and Cochrane Library database, from the earliest available date of indexing through May 31, 2017, were searched for studies evaluating the diagnostic performance of F-18 FDG PET or PET/CT for prediction of malignant potential of GIST. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. Across seven studies (188 patients), the pooled sensitivity for F-18 FDG PET or PET/CT was 0.88 (95% confidence interval [CI]: 0.80-0.94) without heterogeneity (χ2 =6.15, P=0.72) and a pooled specificity of 0.88 (95% CI: 0.75-0.94) with heterogeneity (χ2 =23.2, P=0.01). LR syntheses gave an overall LR+ of 7.2 (95% CI: 3.3-15.3) and LR- of 0.13 (95% CI: 0.07-0.24). The pooled diagnostic odds ratio was 54 (95% CI: 16-181). F-18 FDG PET or PET/CT demonstrated good sensitivity and specificity for the prediction of malignant potential of GIST. At present, the literature regarding the use of F-18 FDG PET or PET/CT for the prediction of malignant potential of GIST remains still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of F-18 FDG PET or PET/CT prediction of malignant potential of GIST.

The value of pre- and post-contrast-enhanced ultrasound in evaluation of malignant potential of gastrointestinal stromal tumors

Background: Contrast-enhanced ultrasound (CEUS) permits evaluation of intratumoral vascularity in real time. The purpose of the present study was to compare the performance of conventional ultrasound (US) and CEUS in the evaluation of malignancy risk in patients with gastrointestinal stromal tumors (GISTs).

The value of pre- and post-contrast-enhanced ultrasound in evaluation of malignant potential of gastrointestinal stromal tumors

Background: Contrast-enhanced ultrasound (CEUS) permits evaluation of intratumoral vascularity in real time. The purpose of the present study was to compare the performance of conventional ultrasound (US) and CEUS in the evaluation of malignancy risk in patients with gastrointestinal stromal tumors (GISTs). Methods: In this retrospective study, we included patients with suspected GISTs who underwent conventional US and CEUS preoperatively. Fifty patients with pathologically confirmed GISTs were enrolled. Tumor risk stratifications were determined according to the 2008 NIH criteria. Pre- and post-CEUS findings were reviewed. Tumor size, lobular border, heterogeneity, cystic areas, calcification and intratumoral gas on US, irregular vessels, heterogeneous enhancement, and non-enhancing areas on CEUS were compared among different risk groups of GISTs. The relationship between time-intensity curve parameters and risk stratification was also analyzed. Results: Larger lesion size, lobulation, and cystic areas were associated with higher risk (P 0.05). Visualization of intratumoral irregular vessels and non-enhancing areas on CEUS were significantly correlated with higher risk classification (P Conclusions: The combination of conventional US and CEUS provides valuable information for preoperative risk stratification of GISTs.

Association of endoscopic ultrasonographic parameters and gastrointestinal stromal tumors (GISTs): can endoscopic ultrasonography be used to screen gastric GISTs for potential malignancy?

ABSTRACTBackground: Previous research shows that only 10–30% of gastrointestinal stromal tumors (GISTs) are malignant. Nonetheless, some reports suggest that all of them have some degree of potential for malignancy. Endoscopic ultrasonography (EUS) is a useful technique for differentiation of subepithelial lesions in the gastrointestinal tract. We explored EUS characteristics that might predict the malignancy potential of GISTs. Methods: In this retrospective review of the medical records from 1999 through 2007, patients who had gastric stromal tumors diagnosed prior to surgery using EUS were enrolled. The EUS images, procedure records and tissue histopathology were reviewed. All patients were positive for C-kit. Results: Of the 110 patients enrolled, 57 were males, and 53 were females. Most (67%) of the GISTs were located in the gastric body. The lesion size ranged from 6.3 to 150 mm (mean ± SD: 39.73 ± 22.49 mm). The high-risk GIST group had 19 (17.3%) patients, the intermediate-risk group had 12 (10.9%) patients and the low/very low-risk group had 79 (71.8%) patients. Thirty patients had cystic lesions (27.3%), while six patients had calcification in the lesion (5.5%). Additionally, 27 patients (24.5%) had surface ulceration visible on endoscopy. GISTs at high risk for malignancy were highly associated with lesion size (p<0.0001), cystic change (p=0.015) and surface ulceration (p=0.036) but not with calcification (p=0.667). We also found that mitosis was associated with lesion size (p<0.0001) rather than other parameters. Age was not predictive of malignancy potential (p=0.316). However, tumor size is the only one independent risk factor for malignancy (p ≤ 0.0001). Conclusions: The preliminary results show that large gastric GISTs with cystic change and surface ulceration may associate with a risk of malignancy, warranting more aggressive management. Nevertheless, the tumor size is more important than other factors.

Contrast-enhanced endoscopic ultrasonography can predict a higher malignant potential of gastrointestinal stromal tumors by visualizing large newly formed vessels.

The aim of this study was to elucidate the histologic and clinical implications of detection of intratumoral vessels on contrast-enhanced endoscopic ultrasonography (CE-EUS) in gastrointestinal stromal tumors (GISTs). Thirteen patients with a GIST, all of whom were referred for surgery, underwent presurgical CE-EUS. The malignant potential, assessed according to the modified Fletcher risk classification system, and the histologic degree of angiogenesis were compared with the presence or absence of intratumoral vessels on CE-EUS. Of the six tumors with intratumoral vessels observed on CE-EUS, five were intermediate- or high-risk GISTs, and the remaining seven negative cases were categorized as very low risk or low risk. The presence of intratumoral vessels on CE-EUS was significantly correlated with a higher-risk classification (p = 0.005). On histologic examination, all GISTs having visualized vessels incorporated vessels of more than 500 μm in diameter. The large intratumoral vessels of the five intermediate- or high-risk GISTs lacked elastic fibers, suggesting that they were neovascular in nature. These higher-risk tumors were also found, by immunohistochemical analysis, to have high expression of vascular endothelial growth factor. Intratumoral vessels observed in GISTs on CE-EUS are correlated with a higher degree of angiogenesis, resulting in higher malignant potential.

The Usefulness of Preoperative 18FDG Positron-Emission Tomography and Computed Tomography for Predicting the Malignant Potential of Gastrointestinal Stromal Tumors

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The tumor size and mitotic count, typical risk category factors, are difficult to determine preoperatively. This study aimed to evaluate the usefulness of preoperative 18F-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT) for predicting the malignant potential of GISTs by analyzing the correlation between the maximum standardized uptake value (SUVmax) and postoperative factors. Methods: Thirty consecutive patients underwent surgery after preoperative 18FDG-PET/CT and were diagnosed with pathologically confirmed GIST. The tumor size, mitotic count, MIB-1 index and National Institutes of Health (NIH) risk category were compared with SUVmax. Results: Significant correlations between SUVmax and tumor size and NIH risk category were determined. The sensitivity and specificity of SUVmax for predicting the risk of malignancy were 85.7 and 62.5%, respectively. The optimal cut-off value for SUVmax was 3.0 between patients classified into low-risk and high-risk malignancy groups. There was no significant correlation between SUVmax and mitotic count or MIB-1 index. Multivariate analysis indicated that SUVmax was the only predictive risk factor in the high-risk malignancy group. Conclusions: 18FDG-PET/CT is useful for assessing the malignant potential and bioactivity of GISTs. When SUVmax is >3.0, the tumor must be resected even if it measures <2 cm, because of its high malignant potential.

Contrast‐enhanced endoscopic ultrasound

Compared to other imaging modalities, endoscopic ultrasound (EUS) has limitations in terms of image enhancement. However, with the availability of contrast agents in ultrasonography, EUS has evolved. Contrast-enhanced Doppler EUS (CD-EUS) enhances Doppler signals from vessels and is useful for characterizing lesions detected by EUS. Moreover, contrast-enhanced harmonic EUS (CH-EUS) with second-generation ultrasound contrast agents and a broad band transducer allows microvessels and parenchymal perfusion to be visualized. Vascularity can also be quantitatively analyzed during CH-EUS by generating a time-intensity curve. CE-EUS is useful for characterizing pancreatic lesions and can detect pancreatic adenocarcinomas with a sensitivity of 94%and a specificity of 89% as a result of the hypo-enhancement of these lesions. Indeed, CH-EUS is superior to multiple detector-computed tomography in terms of the differential diagnosis of small lesions that are ≤2 cm. CH-EUS complements EUS-guided fine-needle aspiration (EUS-FNA) as it identifies the EUS-FNA target and lesions with false-negative EUS-FNA findings. CH-EUS is also used to estimate the malignant potential of gastrointestinal stromal tumors and helps to differentiate between malignant and benign lymphadenopathy.

Clinical Features and Risk Factors of Gastric Subepithelial Tumor Needed Surgery in Clinical Practice: A Single-center Retrospective Study

Background/Aims: Gastric subepithelial tumor (SET) is often noted incidentally during esophagogastroduodenoscopy (EGD). The prevalence of SET is increasing in accordance with the increase of EGD and endosonographies. SET can range from benign lesions to tumors with malignant behavior or potential such as gastrointestinal stromal tumor (GIST) and carcinoid tumor. The aim of this study was to evaluate clinical features and risk factors of gastric SET that needed surgery in a single center. Materials and Methods: We retrospectively analyzed medical records of 90 patients who underwent operations due to SET during the period from January 2006 to December 2010. Results: Of the 90 patients, those who were diagnosed with GIST, ectopic pancreas, leiomyoma, schwannoma, carcinoid tumor, and inflammatory fibroid polyp after surgery were 43 (47.8%), 14 (15.6%), 13 (14.4%), 8 (8.9%), 3 (3.3%), and 2 (2.2%), respectively. Most patients who received operation due to SET were asymptomatic (52.2%). Patients were divided into non-GIST and GIST groups, non-malignant and malignant groups, respectively. Baseline characteristics between both groups were significantly different in age, and size (P＜0.05). Age was an independent risk factor of malignant gastric SET (OR, 1.045; 95% CI, 1.008∼1.084; P=0.016). In addition, age and size were independent risk factors of gastric SET with potential of GIST (OR, 1.049; 95% CI, 1.011∼ 1.089; P=0.011, OR, 1.026; 95% CI, 1.002∼1.050; P=0.031). Conclusions: We demonstrated that an independent risk factor of malignant gastric SET that needed surgery was age, and independent risk factors of GIST were age and size of the tumor. (Korean J Helicobacter Up Gastrointest Res 2013;13:44-49)

The efficacy of PET-CT for predicting the malignant potential of gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the intestinal tract. The risk category is usually determined by tumor size and mitotic count, but accurate preoperative diagnosis of GIST is very difficult. The purpose of this study is to evaluate the efficacy of positron emission tomography(PET)-CT for predicting the malignant potential of gastrointestinal stromal tumors. Ten patients with GIST who underwent a preoperative PET-CT examination were divided into two groups by risk category, and various factors were compared between the two groups. The relationships between the maximum standardized uptake value (SUVmax) and GIST parameters were examined. Patients were classified into two groups by their risk category: (low/intermediate-risk or high-risk). The SUVmax was significantly higher in the high-risk group (11.0±3.04) than in the low/intermediate-risk group (2.1±1.5). The Ki67 labeling index was also significantly higher in the high-risk group (8.63±6.2) than in the low/intermediate-risk group (1.75±0.52). There was a significant correlation between the Ki67 labeling index and the SUVmax (p=0.028) and between the mitotic index and the SUVmax (p=0.029). PET-CT can predict malignant potential. Cases with a SUVmax of over 5 may have malignant potential.

Abstract LB-471: Upregulation of miR-196a and HOTAIR is associated with the malignancy of gastrointestinal stromal tumors

Abstract Although dysregulation of microRNA (miRNA) expression is a common feature of human malignancies, its involvement in gastrointestinal stromal tumors (GISTs) is not fully understood. In the present study, we aimed to identify miRNAs associated with the malignant potential of GISTs. miRNA microarray analysis enabled us to detect the frequent upregulation of miR-196a in high-risk GISTs. Quantitative RT-PCR analysis of 56 fresh frozen and 100 formalin-fixed paraffin-embedded (FFPE) specimens confirmed that overexpression of miR-196a is associated with a high-risk grade, metastasis and poor survival among GIST patients (hazard ratio, 9.1; P &amp;lt; 0.001). The miR-196a genes are located within the HOX gene clusters, and gene expression microarray analysis revealed that HOXC genes and a large intergenic non-coding RNA (lincRNA), HOTAIR, were concurrently upregulated in GISTs overexpressing miR-196a. Elevated HOTAIR expression was also strongly associated with the high-risk category, metastasis and poor clinical outcome of GISTs (hazard ratio, 9.0; P = 0.034). RNAi-mediated knockdown of HOTAIR suppressed the invasiveness of GIST cells, and induced a significant change in the expression profile of genes that included previously reported HOTAIR target genes. This is the first report of concurrent overexpression of HOX genes and collinear non-coding RNAs in human malignancy, and our data suggest that miR-196a and HOTAIR could be useful biomarkers and novel therapeutic targets in malignant GISTs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-471. doi:1538-7445.AM2012-LB-471

Predicting Metastatic Potential of Gastrointestinal Stromal Tumors in Dog by Ultrasonography

Gastrointestinal stromal tumor (GIST), a mesenchymal neoplasm affecting the gastrointestinal tract, shows a variety of clinical behaviors from inactive benign to aggressive malignant in dogs. In this study, the feasibility of using clinically significant ultrasonographic features to predict the metastatic potential of canine GIST was investigated through comparison with actual metastatic incidence and findings of malignancy obtained by postoperative pathological examination. Ultrasonographic features, including large tumor size, irregular margin and heterogeneous internal echogenicity with large hypoechoic areas, related closely with the presence of metastasis as well as a high-risk ranking by the human classification system according to pathological findings. Based on these ultrasonographic features, the potential of metastasis in canine GIST could be preoperatively predicted.