Nuclear MUM1 positive plasma cell in a patient with Plasma cell Myeloma


  • MUM1 (Multiple myeloma oncogene-1)
  • IRF4 (Interferon regulatory factor 4)


Technical InfoEdit

Staining PatternEdit

  • Nuclear (like all transcription factors)

Expression in Normal TissuesEdit

  • Melanocytes
  • Germinal center B-cells from the light zone (not the dark zone)

Expression in Neoplastic EntitiesEdit

Tumor name % Positive Staining Number of Cases

Intermediate/Uncertain Malignant PotentialEdit
Tumor name % Positive Staining Number of Cases

Tumor name % Positive Staining Number of Cases

  • Multiple myeloma
  • Activated (non-germinal center) type of diffuse large B-cell lymphoma (DLBCL)[1]
  • Reed-Sternberg / Hodgkin cells
  • Melanoma (some)[2]

Expression in Non-Neoplastic EntitiesEdit

Pertinent NegativesEdit

This antigen is typically NOT expressed by the following entities:

Practical Uses / PanelsEdit

Common PitfallsEdit

Related Links/Other ResourcesEdit


  1. Mod Pathol. 2004 Jul;17(7):847-56.
  2. Mod Pathol 2001;14(7):686–694

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