Hematological neoplastic markers

Question 1

AML vs ALL

Answer 1

• AML: MPO, CD33, CD13
• Acute Promyelocytic Leukemia: MPO, CD33 and CD34 negative
  
  • Diagnostic test – cytogenetics t 15,17 translocation (PML-RARA)
• ALL –CD34, TDT in both B and T ALL
• Progenitor B cell
  –CD79a, CD19, CD10, PAX5,
  –Absent surface immunoglobulin and rarely CD20+ ( markers associated mature B cells)
• T cell ALL
  –Cytoplasmic CD3 (not surface)
  –Variable expression:
  
  • CD2, CD7, sometimes CD1a and CD5
  • Coexpression CD4/8
• CD34+ - stem cell marker common in both ALL and AML
• Immature blasts poorly differentiated often morphologically indistinguishable

Question 2

Key Markers for B cell NHL

Answer 2

• CLL – Unique immunophenotype
  
  • –CD19, CD 20 (dim), CD23 and CD5
  • –Dim surface immunoglobulin expression – early B cell
• Mantle cell NHL – CD19/20, CD5 (cyclin D1+)
• Follicular Lymphoma - CD19, 20 and CD10
• Hairy cell leukemia –CD19/20. CD25, CD103
• Plasma cells – CD38/138, cytoplasmic light chain restriction

Question 3

Key molecular diagnostic (translocation)

Answer 3

Translocation 15,17 ( PML-RARA)à Acute promyelocytic leukemia

Translocation 9,22 (BCR-ABL)àCML

Translocation 8, 14 (c-MYC –IGH)à Burkitts

Translocation 14, 18 (BCL2 –IGH)à often Follicular NHL

Translocation 11, 14 (CCND1–IGH)à Mantle cell NHL