Expression of DOG1, CD117 and PDGFRA in gastrointestinal stromal tumors and correlations with clinicopathology

Endoscopic obturation with tissue adhesive for bleeding gastric stromal tumor: a case report

Primary endoscopic hemostasis for bleeding gastrointestinal stromal tumor (GIST) is rarely reported. Herein, we report the case of a patient with a bleeding GIST that was treated with endoscopic obturation with tissue adhesive. A 46-year-old man presented with hematemesis and tarry stool for 1 day. Upper GI endoscopy revealed a bleeding submucosal tumor at the stomach fundus and an exposed pulsatile vessel was seen at the defect. Endoscopic obturation with tissue adhesive was performed to treat the defect and the bleeding was successfully stopped. No recurrence of bleeding was observed through a gastric tube, and 6 days after endoscopic obturation, the patient underwent laparoscopic partial gastrectomy. Endoscopic obturation with tissue adhesive is a feasible and effective method to treat bleeding GIST.

Prevalence, diagnosis, and treatment of primary hepatic gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST), which is the most common mesenchymal tumor of the digestive tract, account for 1%-3% of gastrointestinal tumors. Primary stromal tumors outside the gastrointestinal tract are collectively referred to as extra GISTs, and stromal tumors in different regions often have different prognoses. A primary hepatic GIST is a rare tumor with an unknown origin, which may be related to interstitial Cajal-like cells. Although primary hepatic GIST has certain characteristics on imaging, it lacks specific symptoms and signs; thus, the final diagnosis depends on pathological and genetic evidence. This review summarizes all cases of primary hepatic GIST described in the literature and comprehensively analyzes the detailed clinical data of all patients. In terms of treatment, local resection alone or with adjuvant therapy was the prioritized choice to obtain better disease-free survival and longer survival time. For advanced unresectable cases, imatinib mesylate was applied as the first-line chemotherapy agent. Moreover, transcatheter arterial chemoembolization, radiofrequency ablation, and microwave ablation were shown to improve overall survival for selected patients. Liver transplantation was a final treatment option after resistance to chemotherapy developed.

Role of Novel Marker Discovered on Gastrointestinal Stromal Tumor 1 in Evaluation of Gastrointestinal Stromal Tumors

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising from myenteric ganglion cells, termed interstitial cells of Cajal. GISTs occur predominantly between 40 and 60 years of age. CD34 was the initially used for diagnosing GIST. Due to its low specificity for GISTs, CD34 was replaced by C-KIT, which is a reliable marker. However, 5% GISTs lack C-KIT expression. Recent studies have shown GIST1 (DOG1) to be a more sensitive and specific marker compared to C-KIT and CD34. Aims and Objectives: The aim was to study histomorphology characteristics and risk stratification of all cases previously diagnosed as GISTs, to evaluate these cases for CD117 and DOG1 expression by immunohistochemistry (IHC) and to see whether there was any advantage in using novel markers (i.e. DOG1) as compared to conventional (C-KIT) in GIST at our center. Materials and Methods: Fifty patients with histomorphologic or imaging impression of GIST were subjected to IHC using C-KIT and DOG1. Results and Conclusion: Of 50 cases 47 (94%) were positive for C-KIT, and all 50 (100%) cases were positive for DOG1. Hence, DOG1 was positive even in C-KIT-negative cases. Therefore, our study suggests that DOG1 should be added to workup of suspected cases of GIST along with C-KIT.

Gastrointestinal stromal tumor: clinicopathological characteristics and pathologic prognostic analysis

Objective

This study aimed to understand clinicopathological characteristics of gastrointestinal stromal tumors (GISTs) and correlation between pathologic features and clinical outcome.

Methods

We used 76 cases diagnosed as primary GISTs during January 2007 to July 2017 at Army Institute of Pathology, Thailand. Clinical, survival, and pathological data were collected and analyzed.

Results

Ages of the patients ranged from 15 to 88 years (M:F = 1:1). The most common presentation was gastrointestinal bleeding (39.7%). The most common site was the stomach (64.5%). Tumor size ranged from 0.6 to 25.5 cm (average 8.78 cm). Histologic types were spindle cell type (75%), mixed spindled-epithelioid type (17.1%), and epithelioid type (7.9%). The majority of histologic subtype was diffuse hypercellularity (67.1%). Tumor necrosis was found in 38.1% and 80% showed low mitotic counts. Most gastrointestinal stromal tumors (27.6%) are low-risk category according to Miettinen and Lasota’s algorithm. Metastasis was found in 27.7%, mostly occurs within 2 years, and is correlated with tumor size > 10 cm (P = 0.023), non-spindle cell histologic type (P = 0.027), mitotic count > 5/5mm² (P = 0.000), myxoid change (P = 0.011), and mucosal invasion (P = 0.002). Recurrence was found in 8.1%, mostly occurs within 7 years, and correlated with myxoid change (P = 0.045).

Conclusion

We found that most of GISTs show spindle cell type and low-risk category. Metastasis was correlated with tumor size > 10 cm, non-spindle cell histologic type, mitotic count > 5/5mm², myxoid change, and mucosal invasion. Recurrence was correlated with myxoid change.

Primary Extragastrointestinal Stromal Tumours in the Hepatobiliary Tree and Telocytes

The first decade of the twenty-first century witnessed the presence and light microscopic, immunophenotypic, and ultrastructural characterization of interstitial Cajal-like cells (coined as 'telocytes') in virtually every extragastrointestinal site of the human body by Laurentiu M. Popescu and his co-workers. Not surprisingly, stromal tumours, immunophenotypically similar to that of telocytes [CD117 (c-KIT) +/CD34 +], have also been sporadically reported outside the tubular gut (so-called extragastrointestinal stromal tumours, EGISTs), including the gall bladder, liver, and pancreas. A meticulous literature search from January 2000 to November 2015 have found 9 such case reports of EGISTs in the gall bladder, 16 in the liver, and 31 occurring in the pancreas. The site wise mean age at presentation for these tumours were reported to be 62.2 ± 16.6, 50.9 ± 20.1, and 55.3 ± 14.3 years, respectively. Six of nine EGISTs in the gall bladder were associated with gallstones. On pathological evaluation, these tumours exhibited prominent spindled cell morphology and consistent expression of CD117/c-KIT and CD34 on immunohistochemistry and variable expression of vimentin and α-smooth muscle actin. The biological behaviour of hepatic and pancreatic lesions was favourable compared to that in the gall bladder, following definitive surgery with or without imatinib therapy. While the exact pathophysiologic role played by telocytes in various organs is yet to be fully elucidated, there seems to be a direct link between these enigmatic stromal cells and pathogenesis of gallstones and origin of EGISTs, and a hope for targeted therapies. Furthermore, the possible role of telocytes in hepatic regeneration and liver fibrosis opens a new dimension for futuristic research.

PDGFRA and KIT Mutation Status and Its Association With Clinicopathological Properties, Including DOG1

Most of the gastrointestinal stromal tumors (GISTs) have gain-of-function mutations in the KIT gene, which can be used as a prognostic marker for the biological behavior of tumors, predictive marker for the response of tyrosine kinase inhibitors, and diagnostic marker. Researchers have focused on PDGFRA mutations because of both their prognostic and predictive potential and DOG1 positivity for diagnosis on GISTs. The aim of this study is to investigate the effect DOG1, PDGFRA, and KIT mutations on the prediction of the outcome for GIST management. Polymerase chain reaction was performed for KIT gene exons 9, 11, 13, and 17 and PDGFRA gene exons 12 and 18 with the genomic DNA of 46 GIST patients, and amplicons were sequenced in both directions. Immunocytochemical stainings were done by using primary antibodies. Molecular analysis revealed that the KIT mutation was observed in 63% of all cases, while the PDGFRA mutation was observed in 23.9% of cases. Significant relationships were found between age and KIT mutation, tumor location and KIT mutations, and tumor location and PDGFRA mutations (p ≤ 0.05). DOG1 positivity was detected in 65.2% of all GISTs and DOG1-positive cells had a higher KIT mutation ratio than DOG1-negative cells (p ≤ 0.05). KIT gene exon 11 mutations in DOG1-positive cells was higher than DOG1-negative cells (p ≤ 0.05). Conversely, KIT gene exon 13 mutations were higher in DOG1-negative cells than DOG1-positive cells (p ≤ 0.05). In this study, KIT mutation frequency was found similar with the European population; conversely, PDGFRA mutation frequency was similar with an Asian-Chinese-based study. KIT/PDGFRA mutations and tumor location can be used for the prediction of tumor behavior and the management of disease in GISTs. DOG1 positivity might be a candidate marker to support KIT and PDGFRA mutations, due to the higher DOG1 positivity in KIT exon 11 mutant and stomach- and small intestine-localized GISTs.

Gastrointestinal Stromal Tumors: A Clinicopathologic and Risk Stratification Study of 255 Cases from Pakistan and Review of Literature

PURPOSE

To describe the clinicopathological features of gastrointestinal stromal tumors (GIST) diagnosed in our section and to perform risk stratification of our cases by assigning them to specific risk categories and groups for disease progression based on proposals by Fletcher et al and Miettinen and Lasota.

MATERIALS AND RESULTS

We retrieved 255 cases of GIST diagnosed between 2003 and 2014. Over 59% were male. The age range was 16 to 83 years with a mean of 51 years. Over 70% occurred between 40 and 70 years of age. Average diameter of tumors was 10 cms. The stomach was the most common site accounting for about 40%. EGISTs constituted about 16%. On histologic examination, spindle cell morphology was seen in almost of 85% cases. CD117 was the most useful immunohistochemical antibody, positive in 98%. Risk stratification was possible for 220 cases. Based on Fletcher's consensus proposal, 62.3 gastric, 81.8% duodenal, 68% small intestinal, 72% colorectal and 89% EGISTs were assigned to the high risk category; while based on Miettinen and Lasota's algorithm, about 48% gastric, 100% duodenal, 76% small intestinal, 100% colorectal and 100% EGISTs in our study were associated with high risk for disease progression, tumor metastasis and tumor related death. Follow up was available in 95 patients; 26 were dead and 69 alive at follow up. Most of the patients who died had high risk disease and on average death occurred just a few months to a maximum of one to two years after initial surgical resection.

CONCLUSIONS

Epidemiological and morphologic findings in our study were similar to international published data. The majority of cases in our study belonged to the high risk category.

Parallelism of DOG1 expression with recurrence risk in gastrointestinal stromal tumors bearing KIT or PDGFRA mutations

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are characterized by mutations of KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) or PDGFRA (platelet-derived growth factor receptor α) that may be efficiently targeted by tyrosine kinase inhibitors (TKI). Notwithstanding the early responsiveness to TKI, the majority of GISTs progress, imposing the need for alternative therapeutic strategies. DOG1 (discovered on GIST-1) shows a higher sensitivity as a diagnostic marker than KIT, however its prognostic role has been little investigated.

METHODS

We evaluated DOG1 expression by immunohistochemistry (IHC) in 59 patients with GISTs, and correlated its levels with clinical and pathological features as well as mutational status. Kaplan-Meier analysis was also applied to assess correlations of the staining score with patient recurrence-free survival (RFS).

RESULTS

DOG1 was expressed in 66% of CD117(+) GISTs and highly associated with tumor size and the rate of wild-type tumors. Kaplan-Meier survival analysis showed that a strong DOG1 expression demonstrated by IHC correlated with a worse 2-year RFS rate, suggesting its potential ability to predict GISTs with poor prognosis.

CONCLUSIONS

These findings suggest a prognostic role for DOG1, as well as its potential for inclusion in the criteria for risk stratification.

Histopathological Features of Gastrointestinal Stromal Tumors and the Contribution of DOG1 Expression to the Diagnosis

BACKGROUND

Gastrointestinal stromal tumors (GIST) have KIT or platelet-derived growth factor receptor α (PDGFRα) mutations affecting receptor tyrosine kinase activity and do not benefit from classic treatment regimens.

AIMS

The aim of this study was to review the algorithm that may be followed for the diagnosis and differential diagnosis in GISTs by investigating the histomorphological parameters and expression characteristics of classical immunohistochemical antibodies used in routine tests in addition to DOG1 expression.

STUDY DESIGN

Diagnostic accuracy study.

METHODS

We reevaluated the histological and immunohistochemical parameters of 37 GISTs. The standard immunohistochemical diagnosis and differential diagnosis panel antibodies (CD117, PDGFRα, CD34, vimentin, desmin, SMA, S-100, and Ki67) were studied on the tumor sections. We also used the popular marker DOG1 antibody with accepted sensitivity for GISTs in recent years and the PDGFRα immune marker for which the benefit in routine practice is discussed.

RESULTS

Classification according to progressive disease risk groups of the 37 cases revealed that 54% were in the high risk, 19% in the moderate risk, 16% in the low risk, 8% in the very low risk and 8% in the no risk group. Cytological atypia, necrosis, mucosal invasion and the Ki67 index were found to be related to the progressive disease risk groups of the tumors (p<0.05). Positive immunoreaction was observed with CD117 and PDGFRα in all GISTs in the study (100%). Positivity with the DOG1 antibody was found in 33 (89%) cases. CD34 was positive in 62% (23) of the cases.

CONCLUSION

The CD117 antibody still plays a key role in GIST diagnosis. However, the use of DOG1 and PDGFRα antibodies combined with CD117 as sensitive markers can be beneficial.

Does Immunohistochemistry for Discovered on GIST1 and Minichromosome Maintenance Protein7 Provide Additional Clinicopathological Value in Gastrointestinal Stromal Tumors?

BACKGROUND

The aim of the study was to investigate the expression of discovered on GIST 1 (DOG1) and minichromosome maintenance protein 7 (MCM7) in addition to the traditional markers, C-KIT and Ki-67, in gastrointestinal stromal tumors (GISTs) to specify the diagnosis and to evaluate their clinicopathological significance in GIST patients.

METHODS

Hematoxylin and eosin sections of 43 GISTs were re-examined to review histopathological criteria and risk stratification of these tumors. Immunohistochemistry for DOG1, C-KIT, MCM7, Ki-67 antibodies was performed.

RESULTS

Positive DOG1 and C-KIT expressions were found in 42 (97.7%) and 39 (90.7%) of cases, respectively. DOG1 and C-KIT expression scores were significantly correlated (P < 0.001). Among four C-KIT-negative GISTs, three cases were DOG1-positive. DOG1 was more sensitive and specific than C-KIT in the diagnosis of GISTs. High DOG1 expression scores were significantly associated with tumor size (P = 0.023) and risk (P = 0.037). Significant positive correlation was noted between MCM7 and Ki-67 labeling indices (LIs) (P < 0.001, r = 0.885). MCM7 demonstrated higher proliferation LIs than Ki-67. Significant associations were found between MCM7 and Ki-67 LIs and tumor size (P = 0.001 and 0.003 respectively), mitotic rate (P < 0.001 both) and risk stratification (P < 0.001 both) with a stepwise increase in MCM7 LIs with increasing tumor risk.

CONCLUSION

DOG1 is an important diagnostic tool for GISTs particularly in C-KIT-negative tumors. It may have a role in GISTs tumorogenesis and progression. Despite the established clinicopathological value of Ki-67 in GISTs, detection of MCM7 expression is recommended as a prognostic adjunct, given its better sensitivity for cellular proliferation and stepwise association with tumor risk.

Surgical resection should be taken into consideration for the treatment of small gastric gastrointestinal stromal tumors

BACKGROUND

The National Comprehensive Cancer Network (NCCN) recommends conservative follow-up for gastric gastrointestinal stromal tumors (GISTs) less than 2 cm. The aim of the present study was to investigate the clinical and pathological features of small gastric GISTs, re-evaluate the risk potential, and discuss the treatment strategy of small gastric GISTs.

METHODS

In this retrospective study, 63 cases of small gastric GISTs (less than 2 cm) were resected surgically from May 2010 to March 2013 in our department. Clinicopathological factors were collected and the malignant potential of small gastric GISTs was analyzed.

RESULTS

The mitotic index of 14 out of 63 cases (22.22%) exceeded 5. The malignant potential of small gastric GISTs was related to tumor location (P = 0.0218). The mitotic index of 4 out of 8 GISTs (50%) located in gastric cardia exceeded 5, 8 out 28 GISTs (28.57%) located in the gastric fundus exceeded 5, and only 2 out of 27 GISTs (7.41%) located in the gastric body exceeded 5. We also discovered a good consistency between mitotic index and Ki-67 expression of small gastric GISTs.

CONCLUSIONS

Gastric GISTs less than 2 cm also have malignant potential. Thus, we recommended surgical resection of all small gastric GISTs once diagnosed.