CD Markers

Topic Completed: 1 November 2014

Minor changes: 6 November 2020

Copyright: 2003-2021,, Inc.

PubMed Search: pregnancy-specific beta-1 glycoprotein

Nat Pernick, M.D.
Page views in 2020: 30
Page views in 2021 to date: 4
Cite this page: Pernick N. CD66f. website. Accessed January 16th, 2021.
Definition / general
  • Also called pregnancy-specific beta-1 glycoprotein, PSG1
  • May be involved in immune regulation, protection of fetus from maternal immune system
  • Released into maternal circulation during pregnancy
  • Low levels in maternal blood predict spontaneous abortion
  • References: OMIM #176390
Uses by pathologists
  • No significant clinical use by pathologists
Microscopic (histologic) images

Images hosted on other servers:

Implanted ovum (CD66f+, syncytiotrophoblast)

Normal placenta (CD66f+, trophoblast)

Hydatidiform mole (syncytiotrophoblast)

Invasive mole (CD66f+, large trophoblast cells)


Choriocarcinoma of uterus
(CD66f+, syncytiotrophoblast);
note absence of staining in

Positive staining - normal
  • Syncytiotrophoblasts, fetal liver and myeloid cells
Positive staining - disease
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