prostate-specific membrane antigen

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 . 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 .

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 . PSMA is encoded by a gene (FOLH1) located on the short arm of chromosome 11 .

Advantages

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

Disadvantages

• physiological expression is observed in normal tissue, e.g. lacrimal glands, parotid glands, duodenum, renal tubules, ileum
• experiences overexpression in several other neoplasms e.g. colon cancer, breast cancer, thyroid cancer, renal cell carcinoma

Siehe auch:

• PSMA PET-CT