Proteomic Characterization Identifies Clinically Relevant Subgroups of Gastrointestinal Stromal Tumors.

BACKGROUND & AIMS: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract, and it has high metastatic and recurrence rates. We aimed to characterize the proteomic features of GIST to understand biological processes and treatment vulnerabilities. METHODS: Quantitative proteomics and phosphoproteomics analyses were performed on 193 patients with GIST to reveal the biological characteristics of GIST. Data-driven hypotheses were tested by performing functional experiments using both GIST cell lines and xenograft mouse models. RESULTS: Proteomic analysis revealed differences in the molecular features of GISTs from different locations or with different histological grades. MAPK7 was identified and functionally proved to be associated with tumor cell proliferation in GIST. Integrative analysis revealed that increased SQSTM1 expression inhibited the patient response to imatinib mesylate. Proteomics subtyping identified 4 clusters of tumors with different clinical and molecular attributes. Functional experiments confirmed the role of SRSF3 in promoting tumor cell proliferation and leading to poor prognosis. CONCLUSIONS: Our study provides a valuable data resource and highlights potential therapeutic approaches for GIST.

Efficacy and Safety of Avapritinib in Treating Unresectable or Metastatic Gastrointestinal Stromal Tumors: A Phase I/II, Open-Label, Multicenter Study.

BACKGROUND: Avapritinib is a type 1 kinase inhibitor designed to potently and selectively inhibit oncogenic KIT/PDGFRA mutants by targeting the kinase active conformation. This multicenter, single-arm, open-label, phase I/II bridging study of NAVIGATOR in Chinese patients evaluated the safety and the antineoplastic activity of avapritinib in Chinese patients with unresectable/metastatic gastrointestinal stromal tumors (GIST). METHODS: Phase I comprised dose escalation for safety and phase II dose determination. Phase II comprised dose expansion for safety/efficacy evaluations in patients with PDGFRA D842V mutations or patients having received at least 3 lines of therapy without PDGFRA D842V mutations. The primary endpoints were recommended phase II dose, safety, and Independent Radiology Review Committee (IRRC)-assessed objective response rate (ORR). RESULTS: No dose-limiting toxicities occurred (n = 10); the recommended phase II dose was avapritinib 300 mg once daily orally. Fifty-nine patients initially received avapritinib 300 mg. Common grade ≥3 treatment-related adverse events were anemia, decreased white blood cell count, increased blood bilirubin levels, and decreased neutrophil count. In patients with PDGFRA D842V mutations, IRRC- and investigator-assessed ORRs were 75% and 79%, respectively; clinical benefit rates were both 86%. Median duration of response/progression-free survival were not reached. IRCC- and investigator-assessed ORRs in patients in the fourth- or later-line setting were 22% and 35%, respectively. Median progression-free survivals were 5.6 months for both. Overall survival data were immature and not calculated. CONCLUSION: Avapritinib was generally well tolerated and showed marked anti-tumor activity in Chinese patients with GIST bearing PDGFRA D842V mutations and notable efficacy as fourth- or later-line monotherapy (ClinicalTrials.gov Identifier: NCT04254939).

Neoadjuvant apatinib combined with oxaliplatin and capecitabine in patients with locally advanced adenocarcinoma of stomach or gastroesophageal junction: a single-arm, open-label, phase 2 trial.

BACKGROUND: Adding anti-angiogenics to neoadjuvant chemotherapy for localized gastric cancer is recognized as a promising strategy, but its clinical value remains to be defined. METHODS: This single-center, single-arm, phase 2 trial included patients with locally advanced (cT3/4aN+M0) adenocarcinoma of the stomach or gastroesophageal junction (GEJ) who received three cycles of intravenous oxaliplatin (135 mg/m2 on day 1), oral capecitabine (1000 mg/m2 twice daily on days 1 to 14), and oral apatinib for 21 days (250 mg once daily in the first two cycles, and further increased to 500 mg daily in the third cycle based on whether any adverse event of grade 3 or worse occurred), and an additional cycle of oxaliplatin plus capecitabine, followed by gastrectomy with D2 lymphadenectomy. The primary endpoint was the proportion of patients who achieved an objective response according to RECIST version 1.1. RESULTS: Between April 28, 2017, and October 23, 2019, 37 patients were screened and 35 participants were included. Of the 32 patients assessable for efficacy and safety, objective responses were achieved in 25 (78.1%; 95% confidence interval [CI], 60.0% to 90.7%) patients. Thirty-one (96.9%) patients received R0 resection, two (6.3%) patients achieved pathological complete response, and 11 (34.4%) patients achieved pathological response. At the data cutoff date (September 30, 2021), the median event-free survival was 42.6 (95% CI, 16.2 to not reached) months, and the median overall survival was not reached. The most common grade 3 or 4 treatment-emergent adverse events were hypertension (9/32, 28.1%), thrombocytopenia (7/32, 21.9%), and neutropenia (5/32, 15.6%). Seven (21.9%) patients developed surgical complications, and the most common one was intra-abdominal abscess (4/32, 12.5%). CONCLUSIONS: The concomitant use of apatinib, oxaliplatin, and capecitabine as neoadjuvant therapy showed promising efficacy and manageable safety profile in patients with locally advanced adenocarcinoma of the stomach or GEJ, and further phase 3 study is warranted. TRIAL REGISTRATION: This study was registered with ClinicalTrial.gov ( NCT03229096 ).

THZ1 targeting CDK7 suppresses c-KIT transcriptional activity in gastrointestinal stromal tumours.

BACKGROUND: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract and are characterized by activating mutations of c-KIT or PDGFRa receptor tyrosine kinases (RTKs). Despite the clinical success of tyrosine kinase inhibitors (TKIs), more than half of GIST patients develop resistance due to a second mutation. Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of CDK-activating kinase (CAK), and it plays an important role in the regulation of cell cycle transitions and gene transcription. THZ1, a CDK7 inhibitor, exhibits a dose-dependent inhibitory effect in various cancers. METHODS: Data from the public GEO database and tissue microarray were used to analyse the gene expression levels of CDKs in GISTs. The impact of CDK7 knockdown and the CDK7 inhibitor THZ1 on GIST progression was investigated in vitro using CCK-8, colony formation, and flow cytometry assays and in vivo using a xenograft mouse model. RNA sequencing was performed to investigate the mechanism of GIST cell viability impairment mediated by THZ1 treatment. RESULTS: Our study demonstrated that CDK7 is relatively overexpressed in high-risk GISTs and predicts a poor outcome. A low concentration of THZ1 exhibited a pronounced antineoplastic effect in GIST cells in vivo and in vitro. Moreover, THZ1 exerted synergistic anticancer effects with imatinib. THZ1 treatment resulted in transcriptional modulation by inhibiting the phosphorylation of Ser2, Ser5, and Ser7 within RNA polymerase II (RNAPII). c-KIT, an oncogene driver of GIST, was transcriptionally repressed by THZ1 treatment or CDK7 knockdown. Transcriptome sequencing analysis showed that OSR1 acts as a downstream target of CDK7 and regulates c-KIT expression. Taken together, our results highlight elevated CDK7 expression as a predictor of poor outcome in GIST and present the combination of CDK7 and RTK inhibitors as a potent therapeutic strategy to improve the efficacy of GIST treatment. Video abstract.

Pattern of No. 12a lymph node metastasis in gastric cancer.

OBJECTIVE: The current standard D2 lymphadenectomy for gastric cancer (GC) includes dissection of lymph nodes (LNs) along the proper hepatic artery (No. 12a), however, the survival benefit remains controversial. The purpose of this study was to evaluate the pattern of No. 12a LN metastasis (LNM) in GC and explore the indications for No. 12a LN dissection. METHODS: Medical records of 413 consecutive GC patients who underwent curative surgery in Zhongshan Hospital, Fudan University between January 2015 and December 2018 were enrolled and reviewed retrospectively. The correlation between No. 12a LNM and clinicopathologic characteristics of patients was analyzed. RESULTS: The overall incidence of No. 12a LNM was 2.67% (11/413). Tumor location (P=0.012), depth of tumor infiltration (P<0.01) and N stage (P=0.018) were significant factors associated with No. 12a LNM. All the tumors with No. 12a LNM involved the lower third of the stomach and were in T3-4 stages. Patients with No. 12a LNM had extensive LNM than those without (20.91±4.25vs. 5.0±0.54, P<0.001). For advanced GC patients (stage III/IV) with tumors involving the lower third of the stomach, the incidence of No. 12a LNM increased to 10.7% (11/103). Patients with No. 12a LNM had a significantly poorer recurrence-free survival (RFS) (P=0.005) and overall survival (OS) (P=0.017). According to the result of multivariable Cox regression, No. 12a LNM was not an independent impact factor on RFS and OS. CONCLUSIONS: The overall incidence of No. 12a LNM was low but it was much higher in GC patients who had very advanced tumors involving the lower third of the stomach. No. 12a LN dissection should be considered for these patients to improve the survival outcomes.

Upregulation of ZNF148 in SDHB-deficient gastrointestinal stromal tumor potentiates Forkhead box M1-mediated transcription and promotes tumor cell invasion.

Succinate dehydrogenase (SDH) deficiency is associated with gastrointestinal stromal tumor (GIST) oncogenesis, but the underlying molecular mechanism remains to be further investigated. Here, we show that succinate accumulation induced by SDHB loss of function increased the expression of zinc finger protein 148 (ZNF148, also named ZBP-89) in GIST cells. Meanwhile, ZNF148 is found to be phosphorylated by ERK at Ser306, and this phosphorylation results in ZNF148 binding to Forkhead box M1 (FOXM1). Through the complex formation at the promoter, ZNF148 facilitates Histone H3 acetylation and FOXM1-mediated Snail transcription, which eventually promotes cell invasion and tumor growth. The clinical analysis indicates that SDHB deficiency is associated with elevated ZNF148 levels, and ZNF148-S306 phosphorylation level displays a positive correlation with poor prognosis in GIST patients. These findings illustrate an unidentified molecular mechanism underlying FOXM1-regulated gene transcription related to GIST cell invasion, which highlights the physiological effects of SDHB deficiency on the invasiveness of GIST.

HER2 assessment in locally advanced gastric cancer: comparing the results obtained with the use of two primary tumour blocks versus those obtained with the use of all primary tumour blocks.

AIMS: HER2 is currently the only biomarker used to select eligible patients with advanced gastric cancer (GC) for targeted therapy. The aims of this study were to verify the value of dual-block HER2 assessment and to explore whether increasing the block number is more beneficial by carrying out a randomized prospective cohort study in which dual-block and all-block HER2 assessment were compared in resected specimens of GC. METHODS AND RESULTS: Five hundred and forty-nine resected GC specimens were randomly enrolled into two cohorts: a dual-block group (n = 274) with two primary tumour blocks tested, and an all-block group (n = 275) with all primary tumour blocks tested. Immunohistochemical staining of HER2 was performed. For HER2-equivocal (2+) cases, fluorescence in-situ hybridization (FISH) was performed. As compared with single-block assessment, dual-block assessment increased the HER2 immunohistochemistry (IHC)-positive (3+) rate. The rate with dual-block assessment (11.3%) was significantly higher than that with block 1 assessment (8.8%) (P = 0.016) and block 2 assessment (9.1%) (P = 0.031). Similarly, all-block assessment demonstrated a higher HER2 3+ rate (12.4%) than single-block assessment (block 1, 6.5%; block 2, 6.2%; block 3, 7.2%; block 4, 8.7%) (P < 0.05). HER2 3+ rates of all-block and dual-block assessments showed no significant difference (P = 0.703). After IHC and FISH results had been combined, the HER2-positive rate with all-block assessment (13.5%) was slightly higher than that with dual-block assessment (12.0%), although the difference was not statistically significant (P = 0.62). CONCLUSIONS: Dual-block immunohistochemical assessment is an effective, practical and economic approach that is suitable for the preliminary screening of HER2. We recommend that dual-block HER2 assessment be routinely performed on resected specimens of GC. All-block assessment can be a supplement to dual-block assessment if necessary.

The IGCA staging system is more accurate than AJCC7 system in stratifying survival of patients with gastric cancer in stage III.

BACKGROUND: A new staging system recently proposed by the IGCA has demonstrated a better capacity of stratifying different prognoses for gastric cancer than the 7th edition AJCC staging system (AJCC7). The aim of this study was to evaluate the efficacy of the IGCA system in Chinese patients. METHODS: Medical records of patients with gastric cancer who received curative surgery in our center from January 2003 to December 2011 were reviewed retrospectively. All the lesions were staged according to both AJCC7 and IGCA staging systems. Overall survival (OS) of the patients was used as the observation endpoint. RESULTS: One thousand five hundred twenty-six cases were included in this study. By comparing the AJCC7 system with the IGCA systems, 395 cases were stratified into different stages, most of which were in stage III. The IGCA system could better stratify stage IIIB and IIIC patients (5-year OS, 38.1% vs. 29.0%; P = 0.005) than the AJCC7 system (5-year OS, 38.2% vs. 35.9%; P = 0.148). T3N3bM0, T4aN2M0 and T4aN3bM0 made up 97.5% (385/395) of the stage shift. T3N3bM0, which was stratified to stage IIIB in the AJCC7 system, showed a significant poorer prognosis than T4aN2M0 and T4aN3aM0, which were staged to IIIB and IIIC in the same system. The improper staging was revised in the IGCA staging system. CONCLUSIONS: The IGCA staging system can stratify stage III gastric cancer patients more properly than the AJCC7 system.

PIK3C2A is a gene-specific target of microRNA-518a-5p in imatinib mesylate-resistant gastrointestinal stromal tumor.

Imatinib mesylate resistance occurs in some patients with gastrointestinal stromal tumors (GISTs) during the course of treatment. In this study, we investigated the relationship between microRNAs (miRNAs) and imatinib-resistant GISTs, and the effect of miR-518a-5p on PIK3C2A in imatinib-resistant GISTs. A total of 20 matched-pair GIST samples from imatinib-resistant patients were included in the study. Each of the paired tumor specimens were from the same patient who had surgical removal of GISTs preimatinib and postimatinib treatment. Seven pairs of tissues were resected for microarray analysis, and the remaining 13 pairs were utilized for miRNAs analysis. Target genes were selected based on bioinformatics from multiple biological databases. Luciferase reporter assays were used to confirm the binding of miR-518a-5p to PIK3C2A 3'UTR. GIST882R-NC, 882R-miR-518a-5p-OE, and 882R-miR-518a-5p-KD cell lines were constructed using lentiviral vectors. miR-518a-5p and PIK3C2A expression in 882R-NC, 882R-OE, and 882R-KD cells was assessed by real-time PCR and western blotting. A cell counting kit was used to detect the influence of miR-518a-5p to cell proliferation. TUNEL staining was applied to detect the influence of miR-518a-5p to cell apoptosis. Microarray analysis showed that miR-518a-5p was downregulated in imatinib-resistant GISTs, and the expression of miR-518a-5p was confirmed with good concordance between real-time PCR and miRNA microarray results. Luciferase reporter assays indicated that miR-518a-5p bound to the PIK3C2A 3'UTR. Compared with 882R-OE, PIK3C2A expression was significantly increased in 882R-KD cells. MiR-518a-5p reduced 882R proliferation and promoted 882R apoptosis. In conclusion, PIK3C2A is a gene-specific target of miR-518a-5p in imatinib mesylate-resistant GISTs. Low expression of miR-518a-5p is likely to upregulate PIK3C2A and affect the cellular response to the drug, causing resistance to imatinib in GISTs.

Expanded endoscopic therapy criteria should be cautiously used in intramucosal gastric cancer.

OBJECTIVE: Accurate estimation of lymph node metastasis (LNM) in intramucosal gastric cancer is essential to select less invasive treatment options and even avoid surgery. The aim of this study was to evaluate combined clinicopathological features to predict the presence of LNM. METHODS: A retrospective review of data from 386 intramucosal gastric cancer patients who underwent gastrectomy with extended lymphadenectomy from 2003 to 2010 was conducted. The mutual relation between clinicopathological characteristics and LNM was analyzed. RESULTS: LNM was detected in 40 (10.4%) of the 386 patients. Histological type and vascular or lymphatic invasion presence showed a positive correlation with LNM occurrence by univariate analysis. Multivariate analysis revealed that histological type was the only factor associated with LNM. Combined clinicopathologic characteristics would be more predictable for LNM. We found no LNM when we used combined clinicopathological characteristics conforming to Japanese absolute indications for endoscopic therapy. The LNM rate was as high as 8.7% when Japanese expanded criteria were used. Univariate analysis in cancer conformity to expand endoscopic submucosal dissection (ESD) indication also revealed that the undifferential type was the only significant factor for LNM. CONCLUSIONS: It was possible to predict intramucosal gastric cancer cases without LNM using combined clinicopathological characteristic analysis. Extended indication for ESD should be cautiously used for intramucosal gastric cancer patients.

Isolation and culture of hepatic stellate cells from mouse liver.

Hepatic stellate cells (HSCs) are the primary extracellular matrix-producing cells within the liver and have numerous vital functions. A robust protocol for the isolation and culture of HSCs is important for further investigations of cell functions and related mechanisms in liver disease. The volume of the mouse liver is much smaller than that of the rat liver, which makes it much more difficult to isolate mouse HSCs (mHSCs) than rat HSCs. At present, isolating mHSCs is still a challenge because there is no efficient, robust method to isolate and culture these cells. In the present study, C57BL/6J mice were intravenously injected with liposome-encapsulated dichloromethylene diphosphate (CL2MDP) to selectively eliminate Kupffer cells from the liver. The mouse livers were then perfused in situ, and the mHSCs were isolated with an optimized density gradient centrifugation technique. In the phosphate buffer solution (PBS)-liposome group, the yield of mHSCs was (1.37 ± 0.23) × 10(6)/g liver, the cell purity was (90.18 ± 1.61)%, and the cell survival rate was (94.51 ± 1.61)%. While in the CL2MDP-liposome group, the yield of mHSCs was (1.62 ± 0.34) × 10(6)/g liver, the cell purity was (94.44 ± 1.89)%, and the cell survival rate was (94.41 ± 1.50)%. Based on the yield and purity of mHSCs, the CL2MDP-liposome treatment was superior to the PBS-liposome treatment (P < 0.05, P < 0.01). This study established successfully a robust and efficient protocol for the separation and purification of mHSCs, and both a high purity and an adequate yield of mHSCs were obtained.

MiR-320a downregulation is associated with imatinib resistance in gastrointestinal stromal tumors.

Gastrointestinal stromal tumor (GIST) is one of the most common mesenchymal tumors of the gastrointestinal tract. Though imatinib improves the outcome, drug resistance remains the major problem for extending patient survival. Genetic mutation of the drug targets is the known mechanism for imatinib resistance. However, it cannot explain all of the phenomena of imatinib resistance, and numerous additional mechanisms have been proposed to account for imatinib resistance in various model systems. In this study, we applied the SYBR-green quantitative polymerase chain reaction-based array approach to screen the differentially expressed miRNAs between primary GIST patients and imatinib-resistant patients. The selected candidate miRNAs were validated in a cohort of 12 GIST patients. We found that low expression of miR-320a was correlated with short time to imatinib resistance, and proposed the potential mechanism of miR-320a for imatinib resistance.

Safety, effectiveness and the optimal duration of preoperative imatinib in locally advanced gastric gastrointestinal stromal tumors: A retrospective cohort study.

BACKGROUND: The optimal duration of preoperative imatinib (IM) remains controversial. This study aimed to evaluate the safety, therapeutic effectiveness, and optimal duration of preoperative IM in patients with locally advanced gastric gastrointestinal stromal tumors (GIST). METHODS: The clinicopathologic data of 41 patients with locally advanced gastric GIST who received preoperative IM and underwent surgical resection from January 2014 and December 2021 were retrospectively analyzed. RESULTS: After a median of 7.0 (IQR: 4.5-10) months of preoperative IM treatment, 30 patients experienced adverse events (AEs), 80% of which were grade 1/2 AEs. The mean tumor size decreased from 12.71 ± 5.34 cm to 8.26 ± 4.00 cm, with a reduction rate of 35%. Setting 8 months as the cut-off value according to the results of ROC analysis. The proportion of laparoscopic surgery was higher in patients with short-term (≤8 months) versus long-term (>8 months) preoperative IM. Compared with the subtotal/total gastrectomy group, patients in the local gastrectomy group exhibited less intraoperative blood loss, shorter length of postoperative hospital stay, and fewer postoperative complications. The 3-year recurrence-free survival (RFS) and overall survival (OS) rates were 82.9% and 97.6%, and the expected 5-year RFS and OS rates were 75.6% and 90.2% respectively. RFS was better in the short-term than in the long-term preoperative IM treatment group, and it was also better in pre- plus postoperative IM treatment group than that in the preoperative IM alone group. Both univariate and multivariate COX analysis showed that a higher mitotic index and long-term preoperative IM treatment were associated with worse RFS, while postoperative IM treatment could significantly improve RFS. CONCLUSIONS: The study suggests that in patients with locally advanced gastric GIST, preoperative short-term (≤8 months) use of IM is associated with higher RFS than long-term use.

Efficacy and safety of ripretinib vs. sunitinib in patients with advanced gastrointestinal stromal tumor previously treated with imatinib: A phase 2, multicenter, randomized, open-label study in China.

AIM: A bridging study of INTRIGUE study to assess the efficacy and safety of ripretinib versus sunitinib as second-line treatment in Chinese GIST patients. METHODS: This was a phase 2, multicenter, randomized, open-label study in China. GIST patients previously treated with imatinib were randomized (1:1) to receive ripretinib 150 mg once daily (QD) by continuous dosing in 42-day cycles or sunitinib 50 mg QD in 42-day cycles (four weeks on/two weeks off). Primary endpoint was progression-free survival (PFS) by independent radiological review (IRR). RESULTS: Between 6 December 2020 and 15 September 2021, 108 patients were randomized to receive ripretinib (n = 54) or sunitinib (n = 54) (all-patient [AP] intention-to-treat [ITT] population). Seventy patients had primary KIT exon 11 mutations (ripretinib, n = 35; sunitinib, n = 35; Ex11 ITT population). By data cut-off (20 July 2022), in AP ITT population, PFS by IRR was comparable between ripretinib and sunitinib arms (HR 0·99, 95 % CI 0·57, 1·69; nominal p = 0·92; median PFS [mPFS] 10·3 vs 8·3 months). In Ex11 ITT population, PFS by IRR was longer for ripretinib than sunitinib (HR 0·46, 95 % CI 0·23, 0·92; nominal p = 0·03; mPFS not reached in ripretinib arm and 4·9 months in sunitinib arm). Fewer patients experienced grade 3/4 treatment-related treatment-emergent adverse events with ripretinib (17%) versus sunitinib (56%). CONCLUSIONS: Ripretinib demonstrated similar efficacy and a favorable safety profile versus sunitinib as second-line treatment in Chinese GIST patients. Furthermore, ripretinib provided greater clinically meaningful benefit versus sunitinib in patients with KIT exon 11 mutation.

[Screening of differentially expressed microRNAs in borderline and malignant gastrointestinal stromal tumors].

OBJECTIVE: Gastrointestinal stromal tumors (GISTs) have a broad spectrum of biological behaviors ranging from benign, borderline and malignant. This study aimed to screen differentially expressed microRNAs (miRNAs) between malignant and borderline GISTs and to investigate the potential role of miRNAs in the malignant transformation of GISTs. METHODS: Six GIST samples including borderline tumors (n = 3) and malignant tumors (n = 3) were collected based on the clinical and pathological characteristics. Total RNA was extracted, followed by miRNA microarray analysis to screen the differentially expressed miRNAs. The most significantly expressed 4 miRNAs were then chosen for further validation by real-time PCR in 22 additional GIST samples. RESULTS: Direct comparison of malignant group versus borderline group revealed 14 significantly and differentially expressed miRNAs (P < 0.05, with a fold change of < 0.5 or > 2). Five miRNAs were up-regulated and nine were down-regulated in the malignant group. Four miRNAs (miR-221, miR-135b, miR-675(*) and miR-218) were most significantly and differentially expressed between the two groups. The differential expression of 2 miRNAs (miR-221 and miR-675(*)) were subsequently confirmed with good concordance by real-time PCR. CONCLUSIONS: The differential miRNA expression profiles between two groups are revealed by miRNA microarray assay, and confirmed by real-time PCR. Among differentially expressed miRNAs, miR-221 and miR-675(*) might be related to the malignant transformation of GISTs, and have a potential value in predicting biological behavior of GISTs.

New insight on the correlation of immune landscapes with immune markers expression in different risk classification of gastrointestinal stromal tumors.

BACKGROUND: The immune landscapes of gastrointestinal stromal tumors (GISTs) are still unclear. We aimed to explore the immune status of GISTs with different recurrence risks and sought potential immunotherapeutic targets. METHODS: Immune cell infiltration and the expression of 93 tumor markers of 65 GISTs with different recurrence risks from public datasets were analyzed via bioinformatic methods. Infiltrating immune cell and OX40L expression of 417 patients from the Zhongshan cohort were analyzed by immunohistochemistry and immunofluorescence. The clinicopathological data of the patients were collected and the prognostic factors were analyzed by univariate and multivariate methods. RESULTS: Macrophages, T cells and NK cells were the most abundant immune cells in tumor microenvironment. OX40L was the only differentially expressed marker in high- and low-risk patients, as well as in patients with primary and recurrent GIST. The positive rate of OX40L in GIST was 54%. OX40L was highly expressed in patients with no metastasis, low mitotic index and relapse risk. The amount of CD68 + macrophages was the independent factor of OX40L expression. The OX40L expression was positively correlated with M2 and resting mast cells. OX40L co-located with CD4 + T cells, M2 and activated mast cells. Patients with high OX40L levels experienced more prolonged relapse-free survival (RFS). CONCLUSIONS: We first reported that GIST cells could express OX40L, patients with high OX40L experienced longer RFS. The colocalization of OX40L with immune cells indicates that OX40L could be a promising potential target for immunotherapy in GIST.

COLEC12 Promotes Tumor Progression and Is Correlated With Poor Prognosis in Gastric Cancer.

PURPOSE: Collectin subfamily member 12, a transmembrane scavenger receptor C-type lectin, is aberrantly expressed in various cancers. However, its physiological role in gastric cancer remains somewhat unclear. This study aimed to investigate the Collectin subfamily member 12 expression pattern in human gastric cancer and its role in gastric cancer progression. METHODS: The Kaplan-Meier method was used for survival analysis. The univariate and multivariate Cox proportional hazards regression models were used to identify independent predictors for progression-free survival and overall survival. The effects of Collectin subfamily member 12 on gastric cancer cell proliferation, migration, invasion, and apoptosis were detected through the cell counting kit-8 assay, colony formation assay, wound healing assay, transwell assay, and flow cytometry analysis, respectively. Additionally, the correlation between Collectin subfamily member 12 expression and immune cell infiltration was analyzed through bioinformatics. RESULTS: Collectin subfamily member 12 was highly expressed in advanced gastric cancer (T3-T4, pathologic stage III-IV). High Collectin subfamily member 12 expression was correlated with a worse progression-free survival and overall survival in the gastric cancer patients. In vitro, cell line studies revealed that Collectin subfamily member 12 promoted gastric cancer cell proliferation, migration, and invasion and inhibited gastric cancer cell apoptosis. The bioinformatics analysis further demonstrated that the Collectin subfamily member 12 expression level positively correlated with infiltration of several immune cells, such as M2 macrophages, dendritic cells, neutrophils, and regulatory T cells, suggesting that Collectin subfamily member 12 may also play a role in suppressing tumor immune response in gastric cancer. CONCLUSIONS: Collectin subfamily member 12 was identified as a novel predictive marker and target for the clinical treatment of gastric cancer.

Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination.

Imatinib (IM) has significantly improved the prognosis of gastrointestinal stromal tumor (GIST) patients, but some patients still have primary resistance to IM, and approximately half of patients develop acquired drug resistance within 2 years of treatment, necessitating exploration of new treatment strategies. Targeting ferroptosis as a novel approach to tumor treatment has gained attention. Yet, there is limited research on ferroptosis in GIST, and the underlying mechanism remains unclear. In this study, we revealed that IM increased lipid reactive oxygen species and intracellular Fe2+ levels, and decreased glutathione levels in GIST. This effect could be partially inhibited by Ferrostatin-1. Additionally, knocking down STUB1 and overexpressing GPX4 reversed the IM-induced ferroptosis effect. Moreover, STUB1 was identified as a novel E3 ubiquitin ligase of GPX4, promoting the ubiquitination at site K191 of GPX4. The combination of the GPX4 inhibitor RSL3 and IM synergistically induces ferroptosis, inhibiting GIST proliferation both in vivo and in vitro. Furthermore, STUB1 and GPX4 expression serve as independent prognostic factors for GIST. In conclusion, This study is the first to demonstrate that IM induces ferroptosis by promoting STUB1-mediated GPX4 ubiquitination in GIST, and the combination of RSL3 and IM emerges as a promising therapeutic strategy for GIST.

Prognostic analysis of combined curative resection of the stomach and liver lesions in 30 gastric cancer patients with synchronous liver metastases.

BACKGROUND: Gastric cancer with synchronous liver metastasis remains a clinical treatment challenge. There has been a longstanding debate on the question whether surgical resection could be beneficial to long-term survival. This study is to investigate the effectiveness and prognostic factors of combined curative resection of the stomach and liver lesions in gastric cancer patients with synchronous liver metastases. METHODS: A total of 30 patients who underwent simultaneous curative gastric and liver resection from March 2003 to April 2008 were analyzed retrospectively. Univariate and multivariate analyses were performed to select independent factors for survival. RESULTS: The overall 1-, 2-, 3- and 5-year survival rates of 30 patients were 43.3%, 30.0%, 16.7% and 16.7%, respectively, with a median survival of 11.0 months and 5 patients still living by the time of last follow-up. Single liver metastasis (p=0.028) and an absence of peritoneal dissemination (p=0.007) were significantly independent prognostic factors for these gastric cancer patients with synchronous liver metastases. Major adverse events were protracted stomach paralysis in 2 patients and pulmonary infection in another 2 patients, all of whom recovered after conservative treatment. CONCLUSIONS: This descriptive study without control group found that patients with solitary liver metastasis and absence of peritoneal dissemination could have better survival benefit from simultaneous curative resection of the gastric cancer and liver metastases.

Treatment of gastric cancer with dermatomyositis as the initial symptom: Two case reports and review of literature.

BACKGROUND: Dermatomyositis (DM) is a rare autoimmune disease involving the connective tissue. The association between DM and gastric cancer remains unclear. Patients with DM have an increased risk of cancer and higher mortality. It requires immunosuppressive therapy, heightened surveillance, and immunologic response to internal malignancy. CASE SUMMARY: Two cases of gastric cancer with DM as the first symptom in Zhongshan Hospital, Fudan University (Shanghai, China) were reported. Two patients had a typical skin rash. The rash in the first patient involved mainly bilateral upper limbs and neck, while the second patient manifested rash associated mainly with the face, neck, and back. Both manifested muscle weakness in the extremities and elevated serum creatine kinase. Radical resection of the tumor dramatically improved DM-related symptoms in the two patients. The literature review showed that gastric cancer is more commonly associated with DM in middle-aged and older male populations. CONCLUSION: The findings suggest the need for comprehensive screening for malignant tumors in patients with DM refractory to long-term pharmacotherapy or hormone manipulation.