MD Hematology and Oncology 2 — Questions and Answers
Question 1: A 45-year-old presents with fatigue, splenomegaly, and a WBC of 120,000/μL with a left shift. Cytogenetics reveals t(9;22). Which kinase is constitutively activated in this condition?
- JAK2
- BCR-ABL1 (Correct answer)
- FLT3
- KIT
Correct answer: BCR-ABL1
The Philadelphia chromosome t(9;22) creates the BCR-ABL1 fusion gene, producing a constitutively active tyrosine kinase that drives CML.
Question 2: A 70-year-old man has a hemoglobin of 8 g/dL, serum ferritin of 800 ng/mL, low TIBC, and elevated ESR. His anemia is most consistent with:
- Iron deficiency anemia
- Anemia of chronic disease (Correct answer)
- Sideroblastic anemia
- Hemolytic anemia
Correct answer: Anemia of chronic disease
Anemia of chronic disease features low iron, low TIBC, high ferritin (iron trapped in stores), and normal-to-low reticulocytes due to hepcidin-mediated sequestration.
Question 3: A patient on warfarin presents with a PT of 45 seconds and an INR of 4.2, but is not bleeding. The most appropriate next step is:
- Administer IV vitamin K
- Hold warfarin and monitor closely (Correct answer)
- Give fresh frozen plasma
- Give prothrombin complex concentrate
Correct answer: Hold warfarin and monitor closely
For supratherapeutic INR (4.1–10) without bleeding, simply holding warfarin and monitoring is recommended; IV vitamin K is reserved for bleeding or INR >10.
Question 4: Which cytokine is primarily responsible for the thrombocytosis seen in reactive (secondary) thrombocytosis following iron deficiency?
- IL-6
- Thrombopoietin (Correct answer)
- GM-CSF
- IL-11
Correct answer: Thrombopoietin
Thrombopoietin (TPO) levels rise in iron deficiency due to increased erythropoietic drive and cross-stimulation of megakaryocytes, causing reactive thrombocytosis.
Question 5: A 30-year-old woman has episodic hemolysis, pancytopenia, and venous thrombosis. Flow cytometry shows absence of CD55 and CD59 on RBCs. What is the defect?
- Spectrin mutation
- GPI anchor deficiency (Correct answer)
- Band 3 protein loss
- Pyruvate kinase deficiency
Correct answer: GPI anchor deficiency
Paroxysmal nocturnal hemoglobinuria (PNH) results from a PIGA mutation causing GPI anchor deficiency, rendering cells vulnerable to complement-mediated lysis.
Question 6: Which tumor lysis syndrome lab abnormality can directly cause fatal cardiac arrhythmias?
- Hyperuricemia
- Hyperphosphatemia
- Hyperkalemia (Correct answer)
- Hypocalcemia
Correct answer: Hyperkalemia
Hyperkalemia from massive cell lysis is the most immediately life-threatening complication of tumor lysis syndrome due to its cardiac arrhythmogenic potential.
Question 7: A 55-year-old woman with breast cancer develops bone pain and a corrected serum calcium of 13.8 mg/dL. The most likely mediator of humoral hypercalcemia of malignancy is:
- 1,25-dihydroxyvitamin D
- PTH
- PTHrP (Correct answer)
- IL-1β
Correct answer: PTHrP
PTH-related protein (PTHrP) is secreted by many solid tumors and activates PTH receptors in bone and kidney, causing hypercalcemia without elevated true PTH.
MD Hematology and Oncology 2
A 45-year-old presents with fatigue, splenomegaly, and a WBC of 120,000/μL with a left shift.
Cytogenetics reveals t(9;22).
Which kinase is constitutively activated in this condition?