CASE REPORT ON RARE DE-DIFFERENTIATED GIST OF STOMACH OCCURRING DENOVO

We present a rare case of de-differentiated GIST. GIST being the most common mesenchymal tumor of alimentary canal is commonly reported. However, de-defferentiation of GIST is a rare phenomenon which may occur denovo or with imatinib therapy. A 57 year old female patient presented with generalized weakness and anemia. On evaluation, a submucosal lesion on the body of stomach along the greater curvature was identied on UGI endoscopy. On CECT scan of abdomen, polypoidal intraluminal mass was seen. After sleeve gastrectomy histopathological examination showed dedifferentiated GIST, stomach which was conrmed on IHC. The patient had no prior history of Imatinib therapy/ any chemotherapy. We present this case as de-differentiated GIST occurring denovo without prior imatinib therapy is rare and not much is known about its clinical course and prognosis of such cases.

Regulation of miR-126 and miR-122 Expression and Response of Imatinib Treatment on Its Expression in Chronic Myeloid Leukemia Patients

<b><i>Background:</i></b> MicroRNAs (miRNAs) have been observed to exhibit altered expression patterns in chronic myeloid leukemia (CML). Therefore, this study was aimed to evaluate the clinical importance of miR-126 and miR-122 expression in concert to imatinib response in CML patients. <b><i>Methods:</i></b> The present study included 100 CML and 100 healthy subjects. The expression of the 2 miRNAs was performed using TaqMan probe chemistry, and snU6 was used as internal control. <b><i>Results:</i></b> The expression of miR-126 and miR-122 was downregulated in CML patients, with a mean fold change ± SD 0.20 ± 0.33 and 0.22 ± 0.37, respectively. While the expression of both miRNAs was analysed before and after imatinib treatment, it was observed that the expression levels of both were increased after imatinib treatment by 26.25-fold (5.33 against 0.20) and 13.95-fold (3.07 against 0.22) and the increase was statistically significant (<i>p</i> &#x3c; 0.0001 and <i>p</i> &#x3c; 0.0001, respectively). The expression of miR-126 was not conclusive when compared in different clinical stages of the CML disease as it showed a decreased expression in patients with accelerated phase compared to chronic phase (mean fold change = 0.03 and 0.27, respectively), but patients with chronic phase and blastic phase had comparable expression (mean fold change = 0.27 and 0.24, respectively). We also observed an increased expression of both miRNAs after imatinib therapy in each clinical phase. <b><i>Conclusion:</i></b> The study concludes that expression of miR-126 and miR-122 increases after imatinib treatment in CML patients and that miR-126 defines the good responders of imatinib therapy.

Nationwide evaluation of mutation-tailored treatment of gastrointestinal stromal tumors in daily clinical practice

Background Molecular analysis of KIT and PDGFRA is critical for tyrosine kinase inhibitor treatment selection of gastrointestinal stromal tumors (GISTs) and hence recommended by international guidelines. We performed a nationwide study into the application of predictive mutation testing in GIST patients and its impact on targeted treatment decisions in clinical practice. Methods Real-world clinical and pathology information was obtained from GIST patients with initial diagnosis in 2017–2018 through database linkage between the Netherlands Cancer Registry and the nationwide Dutch Pathology Registry. Results Predictive mutation analysis was performed in 89% of the patients with high risk or metastatic disease. Molecular testing rates were higher for patients treated in expertise centers (96%) compared to non-expertise centers (75%, P < 0.01). Imatinib therapy was applied in 81% of the patients with high risk or metastatic disease without patient’s refusal or adverse characteristics, e.g., comorbidities or resistance mutations. Mutation analysis that was performed in 97% of these imatinib-treated cases, did not guarantee mutation-tailored treatment: 2% of these patients had the PDGFRA p.D842V resistance mutation and 7% initiated imatinib therapy at the normal instead of high dose despite of having a KIT exon 9 mutation. Conclusion In conclusion, nationwide real-world data show that over 81% of the eligible high risk or metastatic disease patients receive targeted therapy, which was tailored to the mutation status as recommended in guidelines in 88% of cases. Therefore, still 27% of these GIST patients misses out on mutation-tailored treatment. The reasons for suboptimal uptake of testing and treatment require further study.

Sigmoid Sinus Thrombosis Followed by Splenic Infarction Due to Imatinib Therapy in a Patient with Gastrointestinal Stromal Tumor; Hematological Side Effects of Imatinib

Imatinib has an important place as an adjuvant therapy as well as in the treatment of metastatic disease caused by gastrointestinal stromal tumor (GIST), which is one of the common mesenchymal tumors of the gastrointestinal tract. Imatinib is a tyrosine kinase inhibitor and is generally well tolerated. However, it can cause some serious adverse effects. The most common of these are edema on the face and legs, headache, fatigue, nausea, vomiting, and rash on the skin. The most serious side effects, albeit less common, are gastrointestinal or intraabdominal bleeding. However, thrombotic events such as sigmoid sinus thrombosis and splenic infarction are extremely rare. The current report presents a patient with GIST who is treated with imatinib 400 mg/day. The patient presented with edema on the face and headache in the second month of imatinib therapy, after which she was diagnosed with sigmoid sinus thrombosis. The patient who presented with abdominal pain approximately three months later developed splenic infarction. She was administered acetylsalicylic acid, supplemental oxygen (O2) in the first episode of thrombosis, and imatinib therapy was discontinued. The patient's complaints and thrombus regressed, after which imatinib therapy was resumed. She was administered intravenous hydration, supplemental oxygen, analgesics, and imatinib therapy was discontinued after the patient sustained splenic infarction. After resolution of sigmoid sinus thrombosis and the regression of splenic infarction area, the patient was switched to sunitinib therapy. She is attending routine control visits. Sigmoid sinus thrombosis and splenic infarction should be kept in mind as a rare cause of headache and abdominal pain in patients treated with imatinib, and detailed neurological and gastrointestinal evaluation should be performed.