WBR0487

Author	[[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathophysiology
Sub Category	SubCategory::Oncology
Prompt	[[Prompt::A 36-year-old female presents to the physician's office with complaints of fatigue, loss of energy, and decreased exercise tolerance. She explains that over the past 3-4 months, these symptoms have became increasingly intolerable. Upon physical examination, you note minor splenomegaly. The results from the ordered lab tests are illustrated below. Peripheral blood smear stains demonstrate deficient leukocyte alkaline phosphatase levels. Which of the following treatments is most likely administered to this patient? Hb = 9 Hct = 26.8 MCV = 82 Plt = 120000 WBCs = 24000 %N = 96 %L = 2 ]]
Answer A	AnswerA::Paclitaxel
Answer A Explanation	AnswerAExp::Paclitaxel, not usually used in the treatment of CML, is a microtubule stabilizer.
Answer B	AnswerB::Cytarabine
Answer B Explanation	AnswerBExp::Cytarabine, not usually used in the treatment of CML, is pyrimidine analog.
Answer C	AnswerC::Methotrexate
Answer C Explanation	AnswerCExp::Methotrexate, not usually used in the treatment of CML, is a folic acid analogue.
Answer D	AnswerD::Cisplatin
Answer D Explanation	AnswerDExp::Cisplatin, not usually used in the treatment of CML, is an agent that causes DNa cross-linking.
Answer E	AnswerE::Dasatinib
Answer E Explanation	AnswerEExp::Dasatinib is a tyrosine kinase inhibitor frequently used to treat CML.
Right Answer	RightAnswer::E
Explanation	[[Explanation::Chronic myelogenous/myeloid leukemia (CML), a myeloproliferative disorder accounting for 20% of adult leukemias, is characterized by the increased and unregulated growth of myeloid cells (neutrophils, eosinophils, and basophils), without significant impairment of their differentiating ability. CML is frequently associated with a chromosomal translocation, which is referred to as the Philadelphia chromosome, where a reciprocal translocation between chromosome 9 and 22 occurs (specifically designated as t(9;22)). The translocation results in the bcr-abl genes fusion coding for an oncogenic tyrosine kinase. CML is usually an insidious disease, which is detected incidentally. CML is characterized by low leukocyte alkaline phosphatase staining of peripheral blood and bone marrow aspirates. The tyrosine kinase inhibitor, imatinib, acts by blocking the effects of the bcr-abl gene product. The introduction of tyrosine kinase inhibitors, such as imatinib, asatinib, nilotinib, and bosutinib, increased survival rates dramatically. Educational Objective: CML, characterized by very low leukocyte alkaline phosphatase staining, is frequently treated with tyrosine kinase inhibitors, such as dastinib and imatinib. References: Kantarjian HM, Talpaz M. Chronic myelogenous leukemia. Hematol Oncol Clin N Am. Jun 2004;18(3):XV-XVI.]]
Approved	Approved::Yes
Keyword	WBRKeyword::CML, WBRKeyword::Chronic myelogenous leukemia, WBRKeyword::Imatinib, WBRKeyword::bcr-abl, WBRKeyword::Dasatinib, WBRKeyword::DOC, WBRKeyword::medicine, WBRKeyword::carcinoma, WBRKeyword::leukemia, WBRKeyword::cancer, WBRKeyword::incidental finding, WBRKeyword::enzymes, WBRKeyword::protien
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::