Two different mutational types of familial gastrointestinal stromal tumors:Two case reports

BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors of the gastrointestinal(GI)tract,and cases of GISTs tend to be of the disseminated type,with a global incidence of 10 to 15 cases/million each year.The rarer familial GISTs,which often represent a population,differ in screening,diagnosis,and treatment.Familial GISTs include primary familial GISTs with predominantly KIT/PDGFRA mutations and wild-type GISTs.However,whether the same genetic family has different phenotypes has not been reported.CASE SUMMARY We report two cases of rare GISTs in the same family:A male patient with the V561D mutation in exon 12 of the PDGFRA gene,who has been taking the targeted drug imatinib since undergoing surgery,and a female patient diagnosed with wild-type GIST,who has been taking imatinib for 3 years since undergoing surgery.The favorable prognosis of these patients during the 7-year follow-up period validates the accuracy of our treatment strategy,and we have refined the entire process of diagnosis and treatment of familial GISTs in order to better manage this rare familial disease.CONCLUSION Different mutation types of familial GISTs in the same family are very rare,thus it is very important to make the correct diagnosis and treatment strategies according to the results of molecular detection for the management of familial GISTs.

Extragastrointestinal stromal tumors with diffuse membranous distribution with bleeding:A case report

BACKGROUND Extragastrointestinal stromal tumors(EGIST)and gastrointestinal stromal tumors are of similar pathological type and form.Here we report a rare case of EGIST diffusely distributed in membranous tissue in abdominal cavity,the feature of which included diffuse tumors at membranous tissue in entire abdominal cavity and spontaneous bleeding of the tumors.CASE SUMMARY The patient was a 71-year man and hospitalized due to continuous pain at lower abdomen for more than 10 days.Upon physical examination,the patient had flat and tough abdomen with mild pressing pain at lower abdomen,no obvious abdominal mass was touchable,and shifting dullness was positive.Positron emission tomography-computed tomography(CT)showed that in his peritoneal cavity,there were multiple nodules of various sizes,seroperitoneum,multiple enlarged lymph nodes in abdominal/pelvic cavity and right external ilium as well as pulmonary nodules.Plain CT scanning at epigastrium/hypogastrium/pelvic cavity+enhanced three-dimensional reconstruction revealed multiple soft tissue nodules in abdominal/pelvic cavity,peritoneum and right groin.Tumor marker of carbohydrate antigen 125 was 808 U/mL,diffuse tuberous tumor was seen in abdominal/pelvic cavity during operation with hematocelia,and postoperative pathological examination confirmed EGIST.Imatinib was administered with better therapeutic effect.CONCLUSION Gene testing showed breast cancer susceptibility gene 1 interacting protein C-terminal helicase 1 and KIT genovariation,and the patient was treated with imatinib follow-up visit found that his clinical symptoms disappeared and the tumor load alleviated obviously via imageological examination.

Endoscopic enucleation of gastrointestinal stromal tumors of the stomach: Report of five cases

Gastrointestinal stromal tumor (GIST) of the stomach was treated by endoscopic enucleation in five patients. They were three men and two woman, aged 36-56 years. Tumors located in the cardia were completely enucleated endoscopically without any serious complication. The largest diameter of removed tumors ranged from 1.2 to 2.5 cm. Histopathological diagnosis was GIST with low risk of malignancy (mitotic index < 5/50 high power field) in all cases. The patients were disease-free for 10.5-42.2 mo after endoscopic enucleation.

Gastrointestinal stromal tumor of stomach with inguinal lymph nodes metastasis: A case report

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the alimentary tract. To the best of our knowledge, few cases have been reported in the literature about the peripheral lymph node metastasis of GIST. Here we report an unusual case of gastric GIST with inguinal lymph nodes metastasis. After the metastatic lymph nodes were resected, the. patient started to take imatinib 400 mg/d for 12 mo. There were no signs of tumor recurrence at follow-up after 29 mo. This case suggests that the inguinal lymph nodes can be a potential metastatic site of GIST.

Prognositic factors and clinicopathologic characteristics of small gastrointestinal stromal tumor of the stomach:a retrospective analysis of 31 cases in one center

Objective： To analyze the clinicopathologic characteristics and prognostic factors of small gastrointestinal stromal tumor （GIST） of the stomach. Methods： A total of 31 small gastric GIST patients, including 10 males and 21 females, with a median age of 58 years （37- 81 years）, who underwent surgery at any time from 1999 to 2012 were included in this study. The clinical records of the patients were analyzed retrospectively. Results： Abdominal discomfort and pain （10 cases, 32.3%, respectively） were the two most common complaints among the patients. All patients received surgery, 11 received gastric wedge resection, 11 received subtotal gastrectom）5 5 received laparoscopic gastric wedge resection, and 4 received endoscopic submucosal dissection. No severe adverse complication was observed. A total of 29 patients （93.5%） were followed up. During the follow-up, 2 patients were found to exhibit tumor recurrence, and 1 patient had liver metastases. One patient died of tumor progressionwhile another died of another malignant tumor. Median progression free survival （PFS） time was 120.3 months, and median overall survival （OS） time was 130.4 months. Conclusion： Small gastric GIST has better prognosis. Surgery is the best choice for therapy. Micro-invasive procedures are safe and effective for elective patients. Tumor necrosis, tumor bleeding, and muscle invasion are potential prognostic factors of small gastric GIST.

Gastrointestinal stromal tumor of the stomach with axillary lymph node metastasis: A case report

Gastrointestinal stromal tumors (GISTs) are the most common type of gastrointestinal mesenchymal tumors, although metastasis to the perigastric lymph nodes is relatively rare, compared with liver or peritoneal metastasis. In this report, we describe a case of stomach GIST with a solitary simultaneous metastasis in the left axillary lymph node. A 68-year-old man was diagnosed with a large upper-stomach GIST, and computed tomography and positron emission tomography revealed masses in the left axilla and right mediastinum. We did not detect evidence of metastases to the liver, or other sites including the perigastric lymph nodes, although findings from the surgically resected axillary lymph nodes were compatible with GIST metastasis. Treatment using imatinib markedly reduced the gastric and mediastinal lesions, and this response persisted for 3 years. The patient subsequently experienced rapid growth of the gastric lesion without mediastinal or axilla recurrence, which required palliative surgery. Despite continuing medical treatment(sunitinib and regorafenib), the patient died of liver metastases 23 mo after the surgery. Based on our findings, it appears that the axillary lymph nodes can be a potential metastatic site for GIST metastasis.

Gastric carcinoid tumor in a patient with a past history of gastrointestinal stromal tumor of the stomach

Gastrointestinal stromal tumor is the most common mesenchymal tumor in the gastrointestinal tract. It may coexist with other type of cancers,and if so,the tumors usually involve the stomach. The most common associated cancers are gastrointestinal carcinomas. We report a 65-year-old woman with a history of gastric gastrointestinal stromal tumor who had undergone subtotal segmental gastrectomy. New polypoid lesions were detected on a follow-up gastroscopy one year later. The lesions were biopsied and found to be carcinoid tumors. There was serum hypergastrinemia,and type 1 gastric carcinoid tumor was diagnosed. A total gastrectomy was performed. Pathologic examination revealed both carcinoid tumors and a recurrent gastrointestinal stromal tumor.

Gastrointestinal stromal tumor of the stomach with a giant abscess penetrating the gastric lumen

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. In large GISTs, cystic degeneration, necrosis and focal hemorrhage that occur inside the tumor can result in gastrointestinal bleeding. We describe a case of a 74-year old male with GIST of the stomach accompanied with a giant abscess that penetrated the gastric lumen. The patient experienced undiagnosed fever for two months prior to hospitalization. Gastrointestinal endoscopy, X-ray series and computed tomography of the patient’s abdomen revealed a gastric submucosal tumor in the fornix, with a fistula to the gastric lumen that was inundated with a great deal of pus. The mass was diagnosed as a GIST from biopsy specimens. The patient was treated by endoscopic drainage of the abscess and intravenous administration of antibiotics. Eventually, a partial gastrectomy was performed. He was also administered Imanitib mesylate as adjuvant therapy. He was followed up for 2 years and no metastasis or recurrence was recognized at the follow- up examinations. This is the first report of a patient with clearly diagnosed GIST with endoscopic evidence of an abscess penetrating into the gastric lumen.

DOG1 is useful for diagnosis of KIT-negative gastrointestinal stromal tumor of stomach

Approximately 80%-95%of gastrointestinal stromal tumors(GISTs)show positive staining for KIT,while the other 5%-20%show negative staining.If the tumor is negative for KIT,but is positive for CD34,a histological diagnosis is possible.However,if the tumor is negative for KIT,CD34,S-100,and SMA,a definitive diagnosis is often challenging.Recently,Discovered on GIST-1(DOG1)has received considerable attention as a useful molecule for the diagnosis of GIST.DOG1,a membrane channel protein,is known to be overexpressed in GIST.Because the sensitivity and specificity of DOG1 are higher than those of KIT,positive staining for DOG1has been reported,even in KIT-negative GISTs.KITnegative GISTs most commonly arise in the stomach and are mainly characterized by epithelioid features histologically.We describe our experience with a rare case of a KIT-negative GIST of the stomach that was diagnosed by positive immunohistochemical staining for DOG1 in a patient who presented with severe anemia.Our findings suggest that immunohistochemical staining for DOG1,in addition to gene analysis,is useful for the diagnosis of KIT-negative tumors that are suspected to be GISTs.

Gastrointestinal stromal tumor of the stomach:How to manage?

Gastrointestinal stromal tumor (GIST) is one of the most common malignant mesenchymal tumors of the stomach. Prognosis of this disease is related to tumor size and mitotic activity and early diagnosis is the only way to improve it.Diagnosis of GIST always requires histological and immunohistochemical confirmation as no imaging modalities can diagnose it conclusively.Endoscopic forceps biopsy results are frequently negative. Endoscopic ultrasound-guided fine needle asp- iration (EUS-FNA) is a technique which allows tissue samples to be obtained with minimal risks and is accurate in the diagnosis of GIST. From the point of view of the endoscopist, aggressive use of EUS-FNA is the only promising way to allow early diagnosis and early treatment of this disease.

Synchronous adenocarcinoma and gastrointestinal stromal tumors in the stomach

AIM:To review the clinicopathological characteristics of concurrent gastrointestinal stromal tumors(GISTs) and gastric adenocarcinoma.METHODS:We retrospectively analyzed eight cases of synchronous adenocarcinoma and GIST in the stomach that had been surgically resected with curative intent between March 2003 and December 2008 in Xinhua hospital and Ruijin hospital.The adenocarcinoma was determined to be the primary tumor based on the histological features.The GIST cells were diffusely and strongly positive for CD34 and CD117.RESULTS:The patients were six men and two women aged 47-80 years(average,68.6 years).GIST was preoperatively detected in only one patient.The average sizes of the gastric adenocarcinomas and GISTs were 6.000 ± 2.6186 cm and 1.825 ± 1.4370 cm,respectively.All GISTs were very low-or low-risk lesions that were detected during evaluation,staging,operation or follow-up for gastric adenocarcinoma.CONCLUSION:We hypothesized that the stomach was influenced by the same unknown carcinogen,resulting in a simultaneous proliferation of different cell lines(epithelial and stromal cell).

Clinical course of suspected small gastrointestinal stromal tumors in the stomach

BACKGROUND Gastric subepithelial lesions are frequently encountered during endoscopic examinations,and the majority of them are small and asymptomatic.Among these lesions,gastrointestinal stromal tumors(GISTs)are the major concern for patients and clinicians owing to their malignant potentials.Although previous guidelines suggested periodic surveillance for such small(≤20 mm)lesions,several patients and clinicians have still requested or prescribed repeated examinations or radical resection,posing extra medical burdens and risks.AIM To describe the clinical course of suspected small gastric GISTs and provide further evidence for surveillance strategy for tumor therapy.METHODS This single-center,retrospective study was conducted at West China Hospital,Sichuan University.Consecutive patients with suspected small gastric GISTs were reviewed from November 2004 to November 2018.GIST was suspected according to endoscopic ultrasonography features:hypoechoic lesions from muscularis propria or muscularis mucosa.Eligible patients with suspected small(≤20 mm)GISTs were included for analysis.Patients’demographic data,lesions’characteristics,and follow-up medical records were collected.RESULTS A total of 383 patients(male/female,121/262;mean age,54 years)with 410 suspected small gastric GISTs(1 lesion in 362 patients,2 lesions in 16,3 lesions in4,and 4 lesions in 1)were included for analysis.The most common location was gastric fundus(56.6%),followed by body(29.0%),cardia(12.2%),and antrum(2.2%).After a median follow-up of 28 mo(interquartile range,16-48;range,3-156),402 lesions(98.0%)showed no changes in size,and size of 8 lesions(2.0%)was increased(mean increment,10 mm).Of the 8 lesions with size increment,endoscopic or surgical resection was performed in 6 patients(5 GISTs and 1 leiomyoma).For other 2 remaining patients,unroofing biopsy or endoscopic ultrasound-guided fine-needle aspiration was carried out(2 GISTs),while no further change in size was noted over a period of 62-64 mo.CONCLUSION The majority of suspected small(≤20 mm)gastric GISTs had no size increment during follow-up.Regular endoscopic follow-up without pathological diagnosis may be highly helpful for such small gastric subepithelial lesions.

Gastric IgG4-related disease mimicking a gastrointestinal stromal tumor in a child: A case report

BACKGROUND Gastric IgG4-related disease(IgG4-RD)is rarely encountered in clinical practice,and especially more so among pediatric patients.To our knowledge,this is the first report of IgG4-RD presenting as a calcifying gastric mass in a child.We describe how this entity was difficult to differentiate from a gastrointestinal stromal tumor(GIST)imaging-based approaches.Therefore,this case highlights the importance of considering IgG4-RD in the differential diagnosis of gastric tumor before performing surgical resection,especially to distinguish it from malignancy to avoid unnecessary surgery.CASE SUMMARY The patient suffered from epigastric pain for several days.Panendoscopy and computed tomography scan revealed a submucosal tumor.Differential diagnoses included GIST,leiomyoma,teratoma,and mucinous adenocarcinoma.However,laparoscopic proximal gastrectomy allowed for the definitive diagnosis of IgG4-related stomach disease.CONCLUSION We emphasize the importance of considering IgG4-RD in the differential diagnosis of gastric submucosal tumors before performing surgical resection.

Deep learning model combined with computed tomography features to preoperatively predicting the risk stratification of gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GIST)are prevalent neoplasm originating from the gastrointestinal mesenchyme.Approximately 50%of GIST patients experience tumor recurrence within 5 years.Thus,there is a pressing need to accurately evaluate risk stratification preoperatively.AIM To assess the application of a deep learning model(DLM)combined with computed tomography features for predicting risk stratification of GISTs.METHODS Preoperative contrast-enhanced computed tomography(CECT)images of 551 GIST patients were retrospectively analyzed.All image features were independently analyzed by two radiologists.Quantitative parameters were statistically analyzed to identify significant predictors of high-risk malignancy.Patients were randomly assigned to the training(n=386)and validation cohorts(n=165).A DLM and a combined DLM were established for predicting the GIST risk stratification using convolutional neural network and subsequently evaluated in the validation cohort.RESULTS Among the analyzed CECT image features,tumor size,ulceration,and enlarged feeding vessels were identified as significant risk predictors(P<0.05).In DLM,the overall area under the receiver operating characteristic curve(AUROC)was 0.88,with the accuracy(ACC)and AUROCs for each stratification being 87%and 0.96 for low-risk,79%and 0.74 for intermediate-risk,and 84%and 0.90 for high-risk,respectively.The overall ACC and AUROC were 84%and 0.94 in the combined model.The ACC and AUROCs for each risk stratification were 92%and 0.97 for low-risk,87%and 0.83 for intermediate-risk,and 90%and 0.96 for high-risk,respectively.Differences in AUROCs for each risk stratification between the two models were significant(P<0.05).CONCLUSION A combined DLM with satisfactory performance for preoperatively predicting GIST stratifications was developed using routine computed tomography data,demonstrating superiority compared to DLM.

Insulin-like growth factor 2 targets IGF1R signaling transduction to facilitate metastasis and imatinib resistance in gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GISTs)are typical gastrointestinal tract neoplasms.Imatinib is the first-line therapy for GIST patients.Drug resistance limits the long-term effectiveness of imatinib.The regulatory effect of insulin-like growth factor 2(IGF2)has been confirmed in various cancers and is related to resistance to chemotherapy and a worse prognosis.AIM To further investigate the mechanism of IGF2 specific to GISTs.METHODS IGF2 was screened and analyzed using Gene Expression Omnibus(GEO:GSE225819)data.After IGF2 knockdown or overexpression by transfection,the phenotypes(proliferation,migration,invasion,apoptosis)of GIST cells were characterized by cell counting kit 8,Transwell,and flow cytometry assays.We used western blotting to evaluate pathway-associated and epithelial-mesenchymal transition(EMT)-associated proteins.We injected transfected cells into nude mice to establish a tumor xenograft model and observed the occurrence and metastasis of GIST.RESULTS Data from the GEO indicated that IGF2 expression is high in GISTs,associated with liver metastasis,and closely related to drug resistance.GIST cells with high expression of IGF2 had increased proliferation and migration,invasiveness and EMT.Knockdown of IGF2 significantly inhibited those activities.In addition,OEIGF2 promoted GIST metastasis in vivo in nude mice.IGF2 activated IGF1R signaling in GIST cells,and IGF2/IGF1R-mediated glycolysis was required for GIST with liver metastasis.GIST cells with IGF2 knockdown were sensitive to imatinib treatment when IGF2 overexpression significantly raised imatinib resistance.Moreover,2-deoxy-D-glucose(a glycolysis inhibitor)treatment reversed IGF2 overexpressionmediated imatinib resistance in GISTs.CONCLUSION IGF2 targeting of IGF1R signaling inhibited metastasis and decreased imatinib resistance by driving glycolysis in GISTs.

Effect and safety of ripretinib in the treatment of advanced gastrointestinal stromal tumor:A systematic review and metaanalysis

BACKGROUND Imatinib(IMA)has received approval as the primary treatment for gastrointestinal stromal tumors(GIST).Nonetheless,approximately half of the patients with advanced GIST show disease advancement following IMA treatment.Presently,the efficacy of secondary and tertiary medications in addressing various GIST secondary mutations is somewhat restricted.Consequently,there is a significant medical demand for the creation of kinase inhibitors that extensively block secondary drug-resistant mutations in advanced GIST.Ripretinib(RPT)is a new,switch-control tyrosine kinase inhibitors that can suppress different mutations of KIT and PDGFRA via a dual mechanism of action.AIM To investigate the literature on RPT to assess an effective,safe,and successful treatment strategy against advanced GIST.METHODS The present systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.PubMed,Embase,Cochrane,Web of Science and ClinicalTrials.gov databases were screened from January 1,2003 to May 1,2024.RESULTS A total of 4 studies were included,with a total of 507 patients enrolled.The objective response rate(ORR)of the RPT-treated advanced GIST was 17%(95%CI:0.11-0.27),while the disease control rate(DCR)was 66%(95%CI:0.59-0.73).The overall occurrence of adverse events with varying degrees was 97%(95%CI:0.93-1),whereas that of grade≥3 adverse reactions was 42%(95%CI:0.28-0.63).The sensitivity analysis revealed that omitting some studies did not yield statistically notable variances in the aggregate data regarding the ORR,DCR,and the occurrence of adverse events of grade 3 or higher.The publication bias was absent because no significant asymmetry was observed in Begg’s funnel plot in all studies.CONCLUSION RPT has favorable efficacy profiles in GIST patients,but the adverse reactions are obvious,and patient management needs to be strengthened to achieve better safety and tolerability.

Systemic therapy in gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are the most common type of soft tissue sarcoma in the gastrointestinal tract.Most GISTs have been attributed to activated gain-of-function mutations in either KIT or platelet-derived growth factor receptorα,making these molecular features essential targets for therapeutic interventions.Although surgery is the standard treatment for localized GISTs,patients often experience relapse and disease progression even after surgery.In recent years,targeted therapy has significantly improved the prognosis of patients with advanced GISTs.Imatinib mesylate,a KIT inhibitor,is the first-line treatment for advanced GISTs and has revolutionized the treatment of this disease.However,drug resistance remains a major issue with imatinib treatment,as a significant majority of patients become resistant to imatinib either after initiation or after 2–3 years of treatment.Consequently,novel tyrosine kinase inhibitors such as sunitinib,regorafenib,ripretinib,and avapritinib have been introduced to address drug resistance.Immunotherapy has emerged as a potential approach for the treatment of advanced GISTs.This review comprehensively summarizes the pathogenesis of GISTs and the development of targeted therapies and immunotherapies,provides an overview of the emergence of drug resistance in advanced GISTs,and discusses the challenges and prospects associated with the treatment of GISTs.

Advancing gastrointestinal stromal tumor management: The role of imagomics features in precision risk assessment

BACKGROUND Gastrointestinal stromal tumors(GISTs)vary widely in prognosis,and traditional pathological assessments often lack precision in risk stratification.Advanced imaging techniques,especially magnetic resonance imaging(MRI),offer potential improvements.This study investigates how MRI imagomics can enhance risk assessment and support personalized treatment for GIST patients.AIM To assess the effectiveness of MRI imagomics in improving GIST risk stratification,addressing the limitations of traditional pathological assessments.METHODS Analyzed clinical and MRI data from 132 GIST patients,categorizing them by tumor specifics and dividing into risk groups.Employed dimension reduction for optimal imagomics feature selection from diffusion-weighted imaging(DWI),T1-weighted imaging(T1WI),and contrast enhanced T1WI with fat saturation(CET1WI)fat suppress(fs)sequences.RESULTS Age,lesion diameter,and mitotic figures significantly correlated with GIST risk,with DWI sequence features like sphericity and regional entropy showing high predictive accuracy.The combined T1WI and CE-T1WI fs model had the best predictive efficacy.In the test group,the DWI sequence model demonstrated an area under the curve(AUC)value of 0.960 with a sensitivity of 80.0%and a specificity of 100.0%.On the other hand,the combined performance of the T1WI and CE-T1WI fs models in the test group was the most robust,exhibiting an AUC value of 0.834,a sensitivity of 70.4%,and a specificity of 85.2%.CONCLUSION MRI imagomics,particularly DWI and combined T1WI/CE-T1WI fs models,significantly enhance GIST risk stratification,supporting precise preoperative patient assessment and personalized treatment plans.The clinical implications are profound,enabling more accurate surgical strategy formulation and optimized treatment selection,thereby improving patient outcomes.Future research should focus on multicenter studies to validate these findings,integrate advanced imaging technologies like PET/MRI,and incorporate genetic factors to achieve a more comprehensive risk assessment.

Laparoscopic Submucosal Dissection for Gastrointestinal Stromal Tumor of the Stomach: A Novel Technique for Local Excision with a Minimal Curative Margin

Background: Laparoscopic wedge resection is accepted as a curative treatment for small- and mediumsized gastroin-testinal stromal tumors (GISTs) of the stomach. Conventional methods involving surgical staplers require relatively large lateral margins, which may cause deformity and postoperative dysfunction of the gastric remnant. In this study, we introduce a novel technique called laparoscopic submucosal dissection (LSD) in which the defects of the stomach are minimized and a microscopic negative margin is secured. Methods: The normal seromuscular layer of the gastric wall was dissected with a 5 mm lateral margin. Then, the submucosal tissue was divided carefully using a monopolar electrosurgical device with a curved spatula tip. Results: The operation time was 170 min, and the amount of bleeding was very small. We confirmed an intact pseudo-capsule and marginal subserosal or submucosal tissue of the tumor by histological analysis. The postoperative course was uneventful with no complications. Endoscopy showed minimal deformity of the gastric remnant. Conclusions: We think that LSD is a curative and less invasive treatment for GIST of the stomach. Further investigations are necessary to evaluate the oncological and functional outcomes of this procedure.

TATA-box-binding protein-associated factor 15 is a novel biomarker that promotes cell proliferation and migration in gastrointestinal stromal tumor

BACKGROUND Gastrointestinal stromal tumor(GIST)is a common neoplasm with high rates of recurrence and metastasis,and its therapeutic efficacy is still not ideal.There is an unmet need to find new molecular therapeutic targets for GIST.TATA-boxbinding protein-associated factor 15(TAF15)contributes to the progress of various tumors,while the role and molecular mechanism of TAF15 in GIST progression are still unknown.AIM To explore new molecular therapeutic targets for GIST and understand the biological role and underlying mechanisms of TAF15 in GIST progression.METHODS Proteomic analysis was performed to explore the differentially expressed proteins in GIST.Western blotting and immunohistochemical analysis were used to verify the expression level of TAF15 in GIST tissues and cell lines.Cell counting kit-8,colony formation,wound-healing and transwell assay were executed to detect the ability of TAF15 on cell proliferation,migration and invasion.A xenograft mouse model was applied to explore the role of TAF15 in the progression of GIST.Western blotting was used to detect the phosphorylation level and total level of RAF1,MEK and ERK1/2.RESULTS A total of 1669 proteins were identified as differentially expressed proteins with 762 upregulated and 907 downregulated in GIST.TAF15 was selected for the further study because of its important role in cell proliferation and migration.TAF15 was significantly over expressed in GIST tissues and cell lines.Overexpression of TAF15 was associated with larger tumor size and higher risk stage of GIST.TAF15 knockdown significantly inhibited the cell proliferation and migration of GIST in vitro and suppressed tumor growth in vivo.Moreover,the inhibition of TAF15 expression significantly decreased the phosphorylation level of RAF1,MEK and ERK1/2 in GIST cells and xenograft tissues,while the total RAF1,MEK and ERK1/2 had no significant change.CONCLUSION TAF15 is over expressed in GIST tissues and cell lines.Overexpression of TAF15 was associated with a poor prognosis of GIST patients.TAF15 promotes cell proliferation and migration in GIST via the activation of the RAF1/MEK/ERK signaling pathway.Thus,TAF15 is expected to be a novel latent molecular biomarker or therapeutic target of GIST.