Neoplasia USMLE Step 1 Practice Question
A 60-year-old man presents with recurrent upper gastrointestinal bleeding. Vital signs show BP 128/82 mmHg, HR 92/min, RR 16/min, temp 37.2°C. Hemoglobin is 9.8 g/dL. Upper endoscopy reveals a 3-cm submucosal gastric mass composed of spindle cells that stain positively for CD117 and negatively for S100. Immunohistochemistry confirms CD34 positivity. The patient denies dysphagia or weight loss. Which molecular abnormality most likely drives this neoplasm?
Answer choices
- AALK fusion protein
- BEGFR receptor tyrosine kinase
- CKIT receptor tyrosine kinaseCorrect answer
- DBRAF serine threonine kinase
- EJAK2 tyrosine kinase
- FPDGFRA receptor tyrosine kinase
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