Prostate-specific membrane antigen

Last revised by Daniel J Bell on 8 Jun 2022

Prostate-specific membrane antigen (PSMA), also known as glutamate carboxypeptidase II, is a type II transmembrane glycoprotein that has become an increasingly prominent imaging biomarker 1. PSMA has emerged as a useful target in PET imaging of prostate cancer, especially in the evaluation of small volume lymph node and bone metastases 2.

Its structure consists of 750 amino acids (100-120 kDa), with a 19-amino acid intracellular segment, a 24-amino acid intramembrane component and a 707-amino acid extracellular domain 1. PSMA is encoded by the FOLH1 gene located on the short arm of chromosome 11 7.


  • significantly overexpressed in prostate cancer tissue 2
  • expression is positively correlated with tumor grade, pathological stage and degree of disease recurrence 2
  • PSMA is internalised upon binding, resulting in enhanced tumor uptake and retention 3
  • ideal target for small-molecule radiopharmaceuticals 3


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Cases and figures

  • Case 1: normal physiological distribution
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  • Case 2: F-18 PSMA PET-CT - Normal physiological distribution
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  • Case 3: prostate cancer recurrence
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