Author: Nat Pernick, M.D. (see Authors page)

Revised: 15 December 2015, last major update June 2012

Copyright: (c) 2002-2015,, Inc.

PubMed Search: PU.1 [title]

Cite this page: PU.1. website. Accessed December 15th, 2017.
Definition / general
  • Ets family transcription factor, also known as Spleen focus forming virus Proviral Integration site-1 (Spi1)
  • Transcription factor that plays an essential role in development of lymphoid and myeloid cells by regulating IL7 receptor or macrophage-colony stimulating factor
    • Low PU.1 levels upregulate IL7 receptor expression on common lymphoid progenitor cells, while high levels of PU.1 prevent IL7 receptor expression
  • PU.1 expression is dynamically controlled throughout haematopoiesis to direct appropriate lineage specification (Int J Cell Biol 2011;2011:808524)
  • Nuclear staining
Uses by pathologists
  • Differentiate classic Hodgkin lymphoma (PU.1 negative) from nodular lymphocyte predominant Hodgkin lymphoma (PU.1+, Mod Pathol 2006;19:1010)
Microscopic (histologic) images

Images hosted on Other servers:

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Histiocytic sarcoma

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Positive staining - disease
  • Nodular lymphocyte predominant Hodgkin lymphoma (100%)
  • Follicular lymphoma, mantle cell lymphoma, marginal zone B-cell lymphoma, small lymphocytic lymphoma (100%)
  • Histiocytic / dendritic cell sarcoma (100%, Mod Pathol 2011;24:1421)
  • 50% of diffuse large B cell lymphoma
Negative staining