A multidisciplinary approach in the diagnostic challenge of GIST

Understanding Gastric GIST: From Pathophysiology to Personalized Treatment

Background: Gastric gastrointestinal stromal tumors (GISTs) represent a subset of gastrointestinal tumors predominantly found in the stomach. Despite their rarity, these tumors carry significant implications for patient health and management. GISTs are potentially malignant tumors with unpredictable progression. They originate from the interstitial cells of Cajal, which are positioned between the intramural neurons and the smooth muscle cells of the digestive tract. These tumors are characterized primarily by mutations in the c-Kit gene, as well as other mutations such as those in the platelet-derived growth factor receptor alpha (PDGFRA) gene. Methods: Our comprehensive search across five databases initially yielded 2976 articles. After eliminating 197 duplicates, we screened the titles and abstracts of 2779 articles, excluding 2692 for not meeting the inclusion criteria. During the full-text screening, 16 more articles were excluded. Ultimately, 71 papers met the inclusion criteria and were included in our analysis. Results: Due to differences in study designs, inclusion criteria for patients, and reported outcomes, a meta-analysis was not conducted. The accurate diagnosis of GIST is established through histopathological examination and immunohistochemistry. Histopathologically, GISTs are classified into three main types: spindle cell, epithelioid, and mixed. The therapeutic management of GIST involves surgery, endoscopic treatment, and chemotherapy. Conclusions: The prognosis for GIST patients depends on various factors, including risk category, disease stage, applied treatments, and recurrence post-treatment. A significant recent advancement comes from artificial intelligence, which can be increasingly involved in both the diagnosis and treatment of this tumor.

Optical second-harmonic generation imaging for identifying gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising in the digest tract. It brings a challenge to diagnosis because it is asymptomatic clinically. It is well known that tumor development is often accompanied by the changes in the morphology of collagen fibers. Nowadays, an emerging optical imaging technique, second-harmonic generation (SHG), can directly identify collagen fibers without staining due to its noncentrosymmetric properties. Therefore, in this study, we attempt to assess the feasibility of SHG imaging for detecting GISTs by monitoring the morphological changes of collagen fibers in tumor microenvironment. We found that collagen alterations occurred obviously in the GISTs by comparing with normal tissues, and furthermore, two morphological features from SHG images were extracted to quantitatively assess the morphological difference of collagen fibers between normal muscular layer and GISTs by means of automated image analysis. Quantitative analyses show a significant difference in the two collagen features. This study demonstrates the potential of SHG imaging as an adjunctive diagnostic tool for label-free identification of GISTs.

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

BACKGROUND

Gastric cancer (GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), and genetic components.

AIM

To investigate microbiomes and host genome instability by cost-effective, low-coverage whole-genome sequencing, as biomarkers for GC subtyping.

METHODS

Samples from 40 GC patients were collected from Taizhou Hospital, Zhejiang Province, affiliated with Wenzhou Medical University. DNA from the samples was subjected to low-coverage whole-genome sequencing with a median genome coverage of 1.86 × (range: 1.03 × to 3.17 ×) by Illumina × 10, followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.

RESULTS

Of the 40 GC samples, 20 (50%) were found to be enriched with microbiomes. EBV DNA was detected in 5 GC patients (12.5%). H. pylori DNA was found in 15 (37.5%) patients. The other 20 (50%) patients were found to have relatively higher genomic instability. Copy number amplifications of the oncogenes, ERBB2 and KRAS, were found in 9 (22.5%) and 7 (17.5%) of the GC samples, respectively. EBV enrichment was found to be associated with tumors in the gastric cardia and fundus. H. pylori enrichment was found to be associated with tumors in the pylorus and antrum. Tumors with elevated genomic instability showed no localization and could be observed in any location. Additionally, H. pylori-enriched GC was found to be associated with the Borrmann type II/III and gastritis history. EBV-enriched GC was not associated with gastritis. No statistically significant correlation was observed between genomic instability and gastritis. Furthermore, these three different molecular subtypes showed distinct survival outcomes (P = 0.019). EBV-positive tumors had the best prognosis, whereas patients with high genomic instability (CIN+) showed the worst survival. Patients with H. pylori infection showed intermediate prognosis compared with the other two subtypes.

CONCLUSION

Thus, using low-coverage whole-genome sequencing, GC can be classified into three categories based on disease etiology; this classification may prove useful for GC diagnosis and precision medicine.

Immunohistochemical features of gastrointestinal stromal tumors and their role for differential diagnosis and prognosis

The aim. To clarify all most important immunohistochemical features of gastrointestinal stromal tumors with different histological patterns and analyze the role of expression of Ki-67, MMP-9, VEGF and p16ink4A as a predictive markers of tumor progression. Materials and methods. The study is based on analysis of 100 primary GISTs for description of their morphological features and 36 GISTs taken from this 100 for study of prognostic markers. Results. All spindle cell GISTs have shown diffuse expression of CD117 in tumor cells. The levels of CD117 expression varied from strong expression (3+) until mild expression (1+). Strong expression were seen in 75,8 % of spindle cell GISTs. Epithelioid GISTs demonstrated heterognous moderate or mild expression of CD117. All primary epithelioid GISTs from patients that had relapse of tumor in period from 1 till 3 years demonstrated focal mild expression of CD 117 in tumor cells. Expression of DOG-1 were seen in all 100 cases of GISTs, that were included in our study. The strong expression of DOG-1 (3+) were seen in all 45 GISTs that had low mitotic rate (≤5 mitoses per 50HPF) and not associated with their histological pattern. GISTs with high mitotic rate demonstrated heterogeneous expression of DOG-1 in tumors: moderate expression (2+) with patchy areas of strong expression (3+). Expression of CD56 was not found in spindle cell GISTs, but single tumor cells of epithelioid GISTs that had high mitotic rate demonstrated expression of this marker. The average expression of p16ink4A were higher in tumors that gave relapses compared with tumors without relapses (50,3 % versus 5,7 % respectively, U-test=16.5; p≤0,01).The average expression of MMP-9 also were significantly higher in GISTs that gave relapses: 63,2 % compared with 13,4 % in GISTs without relapse (U-test=16; p≤0 ,01).The strong VEGF expression was found in 66,7 % of GISTs that had relapses and only in 8,3 % of GISTs without relapses. 50 % of GISTs without relapses was negative for VEGF. Finally, the average expression of Ki-67 were 13,4 % in GISTs with relapses and 8,7 % in GISTs without them (U-test=16; p≤0,01). Conclusion. We highly recommend using DOG-1 for epithelioid GISTs. Additionally in epithelioid GISTs can be used CD56 that can give focal positive reaction in some tumour cells. The following minimal panel of markers for differential diagnosis of spindled GISTs from other mesenchymal tumors of gastrointestinal tract is proposed: CD117, DOG-1 and SMA, where the first too markers will demonstrated the moderate or strong diffuse expression and SMA can be occasionally positive in some tumor cells. p16ink4A, ki-67, VEGF and MMP-9 can be used as additional prognostic markers in GISTs.