Expression of the simian virus 40 large tumor antigen (Tag) and formation of Tag-p53 and Tag-pRb complexes in human brain tumors

Cancer. 1999 Nov 15;86(10):2124-32.


Background: The presence of simian virus 40 (SV40) in human brain tumors remains a controversial issue. Even if SV40 does exist in brain tumors, the questions of whether it is associated with brain tumorigenesis and by what mechanisms are unknown.

Methods: SV40 large tumor antigen (Tag) was investigated by immunoprecipitation, silver staining, and Western blot analysis in 65 brain tumor cases and 8 cases of normal brain tissue. Tag-p53 and Tag-pRb complexes were screened by immunoprecipitation and Western blot analysis in 18 and 15 Tag positive tumor tissues, respectively.

Results: Tag was found in all 8 cases of ependymoma and 2 cases of choroid plexus papilloma, 90% of pituitary adenoma cases (9 of 10), 73% of astrocytoma cases (11 of 15), 70% of meningioma cases (7 of 10), 50% of glioblastoma multiforme cases (4 of 8), and 33% of medulloblastoma cases (2 of 6). Five oligodendroglioma cases, 1 pineocytoma case, and 8 cases of normal brain tissue were negative for Tag. The Tag-p53 complex was detected in all 18 Tag positive tumors tested and the Tag-pRb complex was detected in all 15 Tag positive tumors tested.

Conclusions: SV40 Tag not only is expressed in brain tumors; it also can form specific complexes with tumor suppressors p53 and pRb. SV40 is correlated with brain tumorigenesis. The inactivation of p53 and pRb due to the formation of Tag-p53 and Tag-pRb complexes possibly is a significant mechanism in the etiopathogenesis of brain tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antigens, Polyomavirus Transforming / biosynthesis*
  • Blotting, Western
  • Humans
  • Middle Aged
  • Precipitin Tests
  • Retinoblastoma Protein / biosynthesis*
  • Silver Staining
  • Tumor Suppressor Protein p53 / biosynthesis*


  • Antigens, Polyomavirus Transforming
  • Retinoblastoma Protein
  • Tumor Suppressor Protein p53