Molecular Pathogenesis of Gastrointestinal Stromal Tumor: A Paradigm for Personalized Medicine

YAP acts as an independent prognostic marker and regulates growth and metastasis of gastrointestinal stromal tumors via FBXW7-YAP pathway

BACKGROUND

Although imatinib (IM) and subsequent tyrosine kinase inhibitors (TKIs) significantly improve the prognosis of GIST patients by delaying metastasis and recurrence, most patients experience limited efficacy due to toxicity and secondary resistance. We evaluated Yes-associated protein (YAP), a coactivator of the Hippo pathway accounting for IM resistance and aggressive GIST phenotypes, in GISTs. The degradation of YAP is mediated by FBXW7, and FBXW7 predicts recurrence and IM efficacy for GIST patients. Here, we aimed to identify the potential of YAP as a prognostic marker for patients with GISTs, and the molecular mechanism of FBXW7-YAP pathway in GIST cells.

METHODS

We measured YAP expression in 167 GIST cases using immunohistochemical staining, correlated its expression levels with clinicopathological features, and the molecular mechanism underlying the FBXW7-YAP pathway was further examined in vitro and in vivo.

RESULTS

Compared to 80 (47.9%) cases in the low YAP expression group, 87 (52.1%) cases with high YAP expression associated with a poorer prognosis in terms of overall survival (P = 0.004) and recurrence-free survival (P = 0.003). YAP expression was identified as a significant independent factor affecting the 5-year overall survival (P = 0.005) and recurrence-free survival rates (P = 0.007). Moreover, YAP was directly targeted by FBXW7 to affect proliferation, invasion, and migration in GIST cells. High YAP expression correlated with FBXW7 deficiency, as shown in xenograft and metastasis mouse models.

CONCLUSIONS

YAP expression serves as a predictive marker of recurrence for GIST patients with curative resection, highlighting its potential as a novel therapeutic target that warrants further investigation.

SHP2 inhibition and adjuvant therapy synergistically target KIT-mutant GISTs via ERK1/2-regulated GSK3β/cyclin D1 pathway

BACKGROUND

Most gastrointestinal stromal tumours (GISTs) are driven by KIT proto-oncogene, receptor tyrosine kinase (KIT). Targeted treatment with imatinib has been successful in primary GIST patients. However, resistance and relapse gradually develop due to secondary KIT mutations. Identifying novel therapeutic targets for advanced GIST with KIT mutants is critical.

METHODS

Clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 gene editing, immunoblotting, immunoprecipitation and cell-based assays were used to characterise the role of Src homology region 2 domain-containing phosphatase 2 (SHP2) in GIST. Immunoblotting, cell cycle analysis, transcriptome analysis and rescue experiments were performed to investigate the molecular mechanisms underlying SHP2 inhibition. Synergistic effects of SHP2 inhibition with approved KIT tyrosine kinase inhibitors (TKIs) were demonstrated using cell proliferation assay, spheroid formation assay, cell cycle analysis and immunoblotting. The combination of SHP2 inhibition and imatinib was further evaluated in GIST mouse models.

RESULTS

In KIT-mutant GIST, SHP2 was hyperactive and coprecipitated with KIT. Activated SHP2 transduced signals from KIT to the downstream MAPK/ERK pathway. SHP2 inhibition significantly reduced cell viability and arrested cell at G0/G1 phase in GIST cells. Mechanistically, SHP2 regulated the MAPK/ERK, GSK3β/cyclin D1 and mTORC1 pathways in GIST. Specifically, SHP2 inhibition relieved GSK3β self-inhibition, leading to a reduction in cyclin D1 via phosphorylation at Thr286 and subsequent G0/G1 cell cycle arrest. Rescue experiments confirmed that cyclin D1 is functional and critical for cell proliferation. Additionally, SHP2 inhibition synergised with approved KIT TKIs in inhibiting GIST cells. In GIST mouse models, SHP2 inhibitor (SHP099) combined with imatinib significantly inhibited proliferation of imatinib-sensitive and -insensitive GIST cells.

CONCLUSIONS

SHP2 functioned as a key signal transducer for the MAPK/ERK signalling pathway and regulated the cell cycle through GSK3β/cyclin D1/Rb pathway. SHP2 inhibition demonstrates significant efficacy towards GIST cells and synergises with approved TKIs. Therefore, SHP2 represents a promising therapeutic target for advanced GIST.

KEY POINTS

SHP2 plays a pivotal role as a signal transducer in the MAPK/ERK signaling pathway. SHP2 controls the cell cycle via the GSK3β/cyclin D1/Rb pathway in oncogenic KIT-driven GIST. Inhibition of SHP2 synergizes with adjuvant therapy drugs in inhibiting KIT-driven GIST with primary and secondary mutations both in vitro and in vivo.

A rare simultaneous coexistence of pancreatic gastrointestinal stromal tumor and esophageal schwannoma: a case report and review of literature

The concurrent presence of gastrointestinal stromal tumor and schwannoma is extremely rare, and its pathological characteristics remain unclear. This case report reported the diagnostic and treatment process of a patient with a pancreatic GIST coexisting with esophageal schwannoma, who was admitted to West China Hospital (Sichuan, China) in April 2015. The patient did not undergo surgical resection of the tumor but instead received an 8-year regimen of imatinib therapy, during which no tumor progression was observed. However, the patient developed pleural effusion as a result of the localized enlargement of the esophageal schwannoma, which exerted pressure on the right inferior pulmonary vein. This case report provides valuable clinical insights into this distinctive disease presentation.

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.

Ripretinib for the treatment of advanced, imatinib-resistant gastrointestinal stromal tumors

Discovery of constitutive activation of KIT/PDGFRA tyrosine kinases in gastrointestinal stromal tumors (GISTs) leads to the development of the targeted drug imatinib. However, the inevitable development of imatinib resistance remains a major issue. Ripretinib is a novel targeted drug that inhibits the activities of a broad spectrum of drug-resistant KIT/PDGFRA mutants. It was approved in 2020 and is currently recommended by major international guidelines as the fourth-line and beyond therapy for advanced GISTs. Emerging evidence shows that ripretinib is superior to sunitinib as a second-line treatment for KIT exon 11-mutated GISTs due to its activity against highly heterogeneous frequently occurring secondary mutations. This review summarizes current data on the use of ripretinib to treat advanced imatinib-resistant GISTs. We also propose future research directions to improve the targeted GIST treatment.

The immunotherapy in gastrointestinal stromal tumors

Using Tyrosine Kinase Inhibitors (TKIs) for gastrointestinal stromal tumors (GIST) has significantly reduced the risk of recurrence and prolonged survival. Immunotherapy has demonstrated efficacy in multiple solid tumors, but its effectiveness in GIST remains uncertain. Although early clinical studies indicate good tolerability of immunotherapy in patients, the efficacy is not as desired. Therefore, identifying the subset of GIST patients who benefit from immunotherapy and coordinating the relationship between immunotherapy and TKI treatment are crucial issues to be explored. In this review, we aims to provide a retrospective analysis of relevant literature and find that GIST patients exhibit a rich presence of tumor-infiltrating immune cells, which play critical roles in the immune surveillance and evasion processes of tumors. This review incorporates a selection of 48 articles published between 2002 and 2023, sourced from PubMed, EBSCO, and Google Scholar databases.

Computed tomography radiogenomics: A potential tool for prediction of molecular subtypes in gastric stromal tumor

BACKGROUND

Preoperative knowledge of mutational status of gastrointestinal stromal tumors (GISTs) is essential to guide the individualized precision therapy.

AIM

To develop a combined model that integrates clinical and contrast-enhanced computed tomography (CE-CT) features to predict gastric GISTs with specific genetic mutations, namely KIT exon 11 mutations or KIT exon 11 codons 557-558 deletions.

METHODS

A total of 231 GIST patients with definitive genetic phenotypes were divided into a training dataset and a validation dataset in a 7:3 ratio. The models were constructed using selected clinical features, conventional CT features, and radiomics features extracted from abdominal CE-CT images. Three models were developed: ModelCT sign, modelCT sign + rad, and model CTsign + rad + clinic. The diagnostic performance of these models was evaluated using receiver operating characteristic (ROC) curve analysis and the Delong test.

RESULTS

The ROC analyses revealed that in the training cohort, the area under the curve (AUC) values for modelCT sign, modelCT sign + rad, and modelCT sign + rad + clinic for predicting KIT exon 11 mutation were 0.743, 0.818, and 0.915, respectively. In the validation cohort, the AUC values for the same models were 0.670, 0.781, and 0.811, respectively. For predicting KIT exon 11 codons 557-558 deletions, the AUC values in the training cohort were 0.667, 0.842, and 0.720 for modelCT sign, modelCT sign + rad, and modelCT sign + rad + clinic, respectively. In the validation cohort, the AUC values for the same models were 0.610, 0.782, and 0.795, respectively. Based on the decision curve analysis, it was determined that the modelCT sign + rad + clinic had clinical significance and utility.

CONCLUSION

Our findings demonstrate that the combined modelCT sign + rad + clinic effectively distinguishes GISTs with KIT exon 11 mutation and KIT exon 11 codons 557-558 deletions. This combined model has the potential to be valuable in assessing the genotype of GISTs.

Sarco/endoplasmic reticulum calcium ATPase 3 (SERCA3) expression in gastrointestinal stromal tumours

Accurate characterisation of gastrointestinal stromal tumours (GIST) is important for prognosis and the choice of targeted therapies. Histologically the diagnosis relies on positive immunostaining of tumours for KIT (CD117) and DOG1. Here we report that GISTs also abundantly express the type 3 Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA3). SERCA enzymes transport calcium ions from the cytosol into the endoplasmic reticulum and play an important role in regulating the intensity and the periodicity of calcium-induced cell activation. GISTs from various localisations, histological and molecular subtypes or risk categories were intensely immunopositive for SERCA3 with the exception of PDGFRA-mutated cases where expression was high or moderate. Strong SERCA3 expression was observed also in normal and hyperplastic interstitial cells of Cajal. Decreased SERCA3 expression in GIST was exceptionally observed in a zonal pattern, where CD117 staining was similarly decreased, reflecting clonal heterogeneity. In contrast to GIST, SERCA3 immunostaining of spindle cell tumours and other gastrointestinal tumours resembling GIST was negative or weak. In conclusion, SERCA3 immunohistochemistry may be useful for the diagnosis of GIST with high confidence, when used as a third marker in parallel with KIT and DOG1. Moreover, SERCA3 immunopositivity may be particularly helpful in cases with negative or weak KIT or DOG1 staining, a situation that may be encountered de novo, or during the spontaneous or therapy-induced clonal evolution of GIST.

Challenges and opportunities in rare cancer research in China

Cancer is one of the major public health challenges in China. Rare cancers collectively account for a considerable proportion of all malignancies. The lack of awareness of rare cancers among healthcare professionals and the general public, the typically complex and delayed diagnosis, and limited access to clinical trials are key challenges. Recent years have witnessed an increase in funding for research related to rare cancers in China. In this review, we provide a comprehensive overview of rare cancers and summarize the status of research on rare cancers in China and overseas, including the trends of funding and publications. We also highlight the challenges and perspectives regarding rare cancers in China.

Uncommon Association Between Gastrointestinal Stromal Tumors (GIST) and Pheochromocytoma With Abdominal Wall Relapse: Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) represent a rare form of gastrointestinal neoplasm. This report details a medical case involving a 44-year-old woman who underwent bilateral pheochromocytoma resection, GIST gastrectomy, and laparoscopic adrenalectomy with intestinal resection. Despite an initially positive response to oral imatinib, treatment was delayed due to economic constraints. This delay resulted in a critical event marked by abdominal GIST metastasis to the abdominal wall, subsequent rupture leading to hemoperitoneum, and emergency surgery. Following an adequate postsurgical recovery, she was successfully discharged prior to medication adjustments.

The spectrum and significance of secondary (co-occurring) genetic alterations in sarcomas: the hallmarks of sarcomagenesis

Bone and soft tissue tumors are generally classified into complex karyotype sarcomas versus those with recurrent genetic alterations, often in the form of gene fusions. In this review, we provide an overview of important co-occurring genomic alterations, organized by biological mechanisms and covering a spectrum of genomic alteration types: mutations (single-nucleotide variations or indels) in oncogenes or tumor suppressor genes, copy number alterations, transcriptomic signatures, genomic complexity indices (e.g. CINSARC), and complex genomic structural variants. We discuss the biological and prognostic roles of these so-called secondary or co-occurring alterations, arguing that recognition and detection of these alterations may be significant for our understanding and management of mesenchymal tumors. On a related note, we also discuss major recurrent alterations in so-called complex karyotype sarcomas. These secondary alterations are essential to sarcomagenesis via a variety of mechanisms, such as inactivation of tumor suppressors, activation of proliferative signal transduction, telomere maintenance, and aberrant regulation of epigenomic/chromatin remodeling players. The use of comprehensive genomic profiling, including targeted next-generation sequencing panels or whole-exome sequencing, may be incorporated into clinical workflows to offer more comprehensive, potentially clinically actionable information. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Advances in immunology and immunotherapy for mesenchymal gastrointestinal cancers

Mesenchymal gastrointestinal cancers are represented by the gastrointestinal stromal tumors (GISTs) which occur throughout the whole gastrointestinal tract, and affect human health and economy globally. Curative surgical resections and tyrosine kinase inhibitors (TKIs) are the main managements for localized GISTs and recurrent/metastatic GISTs, respectively. Despite multi-lines of TKIs treatments prolonged the survival time of recurrent/metastatic GISTs by delaying the relapse and metastasis of the tumor, drug resistance developed quickly and inevitably, and became the huge obstacle for stopping disease progression. Immunotherapy, which is typically represented by immune checkpoint inhibitors (ICIs), has achieved great success in several solid tumors by reactivating the host immune system, and been proposed as an alternative choice for GIST treatment. Substantial efforts have been devoted to the research of immunology and immunotherapy for GIST, and great achievements have been made. Generally, the intratumoral immune cell level and the immune-related gene expressions are influenced by metastasis status, anatomical locations, driver gene mutations of the tumor, and modulated by imatinib therapy. Systemic inflammatory biomarkers are regarded as prognostic indicators of GIST and closely associated with its clinicopathological features. The efficacy of immunotherapy strategies for GIST has been widely explored in pre-clinical cell and mouse models and clinical experiments in human, and some patients did benefit from ICIs. This review comprehensively summarizes the up-to-date advancements of immunology, immunotherapy and research models for GIST, and provides new insights and perspectives for future studies.

Improving Outcomes in the Advanced Gastrointestinal Stromal Tumors: The Role of the Multidisciplinary Team Discussion Intervention

Objectives: There is disagreement over the prognostic value of multidisciplinary team (MDT) discussion for advanced gastrointestinal stromal tumors (GISTs). This study examined how an MDT affected patients with advanced GISTs in terms of their overall survival (OS) and whether it may enhance their performance status (PS). Methods: A retrospective data analysis was conducted on patients with advanced GISTs between 2000 and 2022. Depending on whether they had received the MDT discussion intervention, the patients were split into two groups. The OS between the two groups was compared using the Kaplan–Meier method. A multivariate Cox regression analysis was used to analyze the prognostic variables for advanced GIST. Fisher’s test was used to investigate the relationship between an MDT and PS. Results: There were 122 patients with an MDT and 117 patients without an MDT in this study. In comparison to the non-MDT group, the MDT group showed a higher survival rate (5-year OS, 42.62% vs. 28.21%, p < 0.05). MDT was an independent prognostic factor for OS in univariate and multivariate Cox regression analyses (p < 0.05). Fisher’s test revealed that there were variations in PS between the two groups (p < 0.05). Conclusions: The effectiveness of an MDT in the treatment of advanced GIST was examined for the first time in this study. MDT discussion intervention is an effective measure for improving the outcomes of patients with advanced GISTs.

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

Simple Summary

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

Abstract

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