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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Ochuko}}
|QuestionAuthor= {{Ochuko}},  {{SSK}} (Reviewed by Serge Korjian)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Genetics, Pathology
|MainCategory=Genetics, Pathology
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|MainCategory=Genetics, Pathology
|MainCategory=Genetics, Pathology
|SubCategory=Oncology
|SubCategory=Oncology
|Prompt=A 14-year-old boy is brought by his parents to the emergency department for severe headaches, dyspnea on exertion and petechiae on the lower extremeties. A CBC was drawn that showed a WBC count of 75, 000/uL, Hb of 8.5g/dl, hematocrit of 22. A bone marrow biopsy performed showed 70% of lymphoid blasts. The blast population expressed CD19, CD20, CD22, CD10 and TdT. The patient was subsequently diagnosed with pre-B acute lymphoblastic leukemia. Which of the following is indicated as a good prognostic marker?
|Prompt=An 7-year-old boy is brought by his parents to the emergency department for severe left leg pain that started 2 days prior to presentation. His mother reports that the child has been very tired for the past few weeks. She also explains that her son has lost a lot of weight, and has been running out of breath with minimal activity recently. Upon further questioning, the child denies any trauma to his leg. On physical exam, you notice an ill appearing child with abdominal swelling and petechiae on the upper and lower extremities. A CBC is drawn and shows a hemoglobin of 8.5 g/dL, hematocrit of 25, and a WBC count of 75,000/uL. Which of the following findings is considered a good prognostic marker in this patient?
|Explanation=The patient in this vignette has Acute Lymphoblastic Leukemia (ALL), which is the most common leukemia in children from newborn to 14 years of age. It is a clonal lymphoid stem cell disease. It could be of the early pre-B-cell leukemia or the T-cell ALL. T(12,21) translocation is the most common structural chromosome change on childhood cancer and is exclusively associated with the B-cell precursor subset of ALL. The translocation generates TEL-AML1 (ETV6-RUNXI) fusion gene, which is associated with a more favorable prognosis as evidenced by a significantly lower relapse rate. Evaluation of this and other prognostic markers helps in selecting low toxicity versus high toxicity therapies
|Explanation=Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, accounting for approximately 30% of all cancers in patients younger than 14 years of age. It is a clonal lymphoid stem cell disease. The classical presentation of patients with ALL includes fatigue, recurrent infections, bony pain, weight loss, easy bruisability, petechiae, dyspnea on exertion, and hepatosplenomegaly. t(12;21) translocation is the most common chromosomal anomaly in childhood leukemias and is exclusively found in patients with Pre-B-ALL (approximately 25% of these patients). The translocation generates TEL-AML1 (ETV6-RUNX1) fusion gene, which is associated with a more favorable prognosis as evidenced by a significantly lower relapse rate. Evaluation of this and other prognostic markers helps in selecting low toxicity versus high toxicity therapies.
 
Educational Objective: t(12,21) translocation is a good prognostic marker in cases of ALL
|AnswerA=t(12;21) translocation
|AnswerA=t(12;21) translocation
|AnswerAExp=t(12, 21) translocation offers a better or favorable prognosis in ALL and this aids in the selection of therapies for cases of ALL
|AnswerAExp=t(12;21) translocation is associated with a favorable prognosis and a lower relapse rate in patients with ALL.
|AnswerB=t(11;22) translocation
|AnswerB=t(11;22) translocation
|AnswerBExp=t(11,22) translocation is associated with Ewing’s sarcoma
|AnswerBExp=t(11;22) translocation is not common among patients with ALL. It is classically associated with Ewing’s sarcoma.
|AnswerC=Ten-eleven translocation 2 (TET2)
|AnswerC=Ten-eleven translocation 2 (TET2) mutation
|AnswerCExp=Ten-eleven translocation 2 (TET2) is a gene located on chromosome 4q24. Mutations’ involving this gene is found in myeloid malignancies including myelodysplastic syndromes, CML, AML. It is not a prognostic indicator in ALL
|AnswerCExp=Ten-eleven translocation 2 (TET2) is a gene located on chromosome 4q24. Mutations involving this gene are found in myeloid malignancies including myelodysplastic syndromes, CML, AML. It is not a prognostic indicator in ALL.
|AnswerD=TdT
|AnswerD=Terminal deoxynucleotidyl transferase (TdT) positivity
|AnswerDExp=TdT is a protein expressed early in the development of pre-T and pre-B cells but it is not a prognostic marker of the disease
|AnswerDExp=TdT is a protein expressed early in the development of pre-T and pre-B cells but it is not a prognostic marker of the disease.
|AnswerE=Isocitrate dehydrogenase 1/2 (IDH1/IDH2)
|AnswerE=Isocitrate dehydrogenase 1/2 (IDH1/IDH2) mutation
|AnswerEExp=Isocitrate dehydrogenase 1 (IDH1) is a gene located in chromosome 2q33.3 while IDH2 is located in chromosome 15q26.1. These genes are responsible for encoding enzymes catalyzing oxidative decarboxylation of isocitrate to alpha ketoglutarate. Mutations in this gene confer poor prognosis in certain subsets of AML
|AnswerEExp=Isocitrate dehydrogenase 1 (IDH1) is a gene located in chromosome 2q33.3 while IDH2 is located in chromosome 15q26.1. These genes are responsible for encoding enzymes catalyzing oxidative decarboxylation of isocitrate to alpha ketoglutarate. Mutations in this gene confer poor prognosis in certain subsets of AML.
|EducationalObjectives=The t(12;21) translocation is a good prognostic marker in cases of acute lymphoblastic leukemia.
|References=Romana SP, Mauchauffé M, Le coniat M, et al. The t(12;21) of acute lymphoblastic leukemia results in a tel-AML1 gene fusion. Blood. 1995;85(12):3662-70.<br>
Borkhardt A, Cazzaniga G, Viehmann S, et al. Incidence and clinical relevance of TEL/AML1 fusion genes in children with acute lymphoblastic leukemia enrolled in the German and Italian multicenter therapy trials. Associazione Italiana Ematologia Oncologia Pediatrica and the Berlin-Frankfurt-Münster Study Group. Blood. 1997;90(2):571-7.
 
|RightAnswer=A
|RightAnswer=A
|WBRKeyword=ALL, Lymphoblast, Blasts, TdT, t(12;21), Acute Lymphocytic Leukemia, Translocations, Prognosis, Genetic anomalies, Pediatric cancers,
|Approved=Yes
|Approved=Yes
}}
}}

Latest revision as of 23:37, 27 October 2020

 
Author [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1], Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Genetics, MainCategory::Pathology
Sub Category SubCategory::Oncology
Prompt [[Prompt::An 7-year-old boy is brought by his parents to the emergency department for severe left leg pain that started 2 days prior to presentation. His mother reports that the child has been very tired for the past few weeks. She also explains that her son has lost a lot of weight, and has been running out of breath with minimal activity recently. Upon further questioning, the child denies any trauma to his leg. On physical exam, you notice an ill appearing child with abdominal swelling and petechiae on the upper and lower extremities. A CBC is drawn and shows a hemoglobin of 8.5 g/dL, hematocrit of 25, and a WBC count of 75,000/uL. Which of the following findings is considered a good prognostic marker in this patient?]]
Answer A AnswerA::t(12;21) translocation
Answer A Explanation AnswerAExp::t(12;21) translocation is associated with a favorable prognosis and a lower relapse rate in patients with ALL.
Answer B AnswerB::t(11;22) translocation
Answer B Explanation AnswerBExp::t(11;22) translocation is not common among patients with ALL. It is classically associated with Ewing’s sarcoma.
Answer C AnswerC::Ten-eleven translocation 2 (TET2) mutation
Answer C Explanation AnswerCExp::Ten-eleven translocation 2 (TET2) is a gene located on chromosome 4q24. Mutations involving this gene are found in myeloid malignancies including myelodysplastic syndromes, CML, AML. It is not a prognostic indicator in ALL.
Answer D AnswerD::Terminal deoxynucleotidyl transferase (TdT) positivity
Answer D Explanation AnswerDExp::TdT is a protein expressed early in the development of pre-T and pre-B cells but it is not a prognostic marker of the disease.
Answer E AnswerE::Isocitrate dehydrogenase 1/2 (IDH1/IDH2) mutation
Answer E Explanation [[AnswerEExp::Isocitrate dehydrogenase 1 (IDH1) is a gene located in chromosome 2q33.3 while IDH2 is located in chromosome 15q26.1. These genes are responsible for encoding enzymes catalyzing oxidative decarboxylation of isocitrate to alpha ketoglutarate. Mutations in this gene confer poor prognosis in certain subsets of AML.]]
Right Answer RightAnswer::A
Explanation [[Explanation::Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, accounting for approximately 30% of all cancers in patients younger than 14 years of age. It is a clonal lymphoid stem cell disease. The classical presentation of patients with ALL includes fatigue, recurrent infections, bony pain, weight loss, easy bruisability, petechiae, dyspnea on exertion, and hepatosplenomegaly. t(12;21) translocation is the most common chromosomal anomaly in childhood leukemias and is exclusively found in patients with Pre-B-ALL (approximately 25% of these patients). The translocation generates TEL-AML1 (ETV6-RUNX1) fusion gene, which is associated with a more favorable prognosis as evidenced by a significantly lower relapse rate. Evaluation of this and other prognostic markers helps in selecting low toxicity versus high toxicity therapies.

Educational Objective: The t(12;21) translocation is a good prognostic marker in cases of acute lymphoblastic leukemia.
References: Romana SP, Mauchauffé M, Le coniat M, et al. The t(12;21) of acute lymphoblastic leukemia results in a tel-AML1 gene fusion. Blood. 1995;85(12):3662-70.
Borkhardt A, Cazzaniga G, Viehmann S, et al. Incidence and clinical relevance of TEL/AML1 fusion genes in children with acute lymphoblastic leukemia enrolled in the German and Italian multicenter therapy trials. Associazione Italiana Ematologia Oncologia Pediatrica and the Berlin-Frankfurt-Münster Study Group. Blood. 1997;90(2):571-7.]]

Approved Approved::Yes
Keyword WBRKeyword::ALL, WBRKeyword::Lymphoblast, WBRKeyword::Blasts, WBRKeyword::TdT, WBRKeyword::t(12;21), WBRKeyword::Acute Lymphocytic Leukemia, WBRKeyword::Translocations, WBRKeyword::Prognosis, WBRKeyword::Genetic anomalies, WBRKeyword::Pediatric cancers
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