Retinoblastoma-like phenotype expressed in medulloblastomas

Pamela B. Jaffey, Gia T. To, Hong Ji Xu, Shi Xue Hu, William F. Benedict, Larry A. Donoso, Gerald A. Campbell

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The previous demonstration of rod-opsin and S-antigen (S-Ag), a protein which arrests visual phototransduction, in retinoblastomas and in a subgroup of medulloblastomas has suggested a relationship between these tumors. We examined 17 medulloblastomas for the presence of a retinoblastoma-like phenotype. Overall 41% of the tumors were immunoreactive for S-Ag. Two tumors with well-differentiated Flexner-Wintersteiner rosettes were also immunoreactive for S-Ag, but not for epithelial membrane antigen (EMA). In contrast, most ependymal rosettes in two ependymomas stained positive for EMA along the luminal surface, consistent with a previous study, and were negative for S-Ag. Because calcification in areas of necrosis is a near constant finding in retinoblastomas, the medulloblastomas were evaluated for the presence of calcification, using Von Kossa staining. Forty-one percent showed calcification in areas of necrosis and 29% were positive for both calcification and S-Ag immunoreactivity. There was a statistically significant concordance between calcification and S-Ag immunoreactivity in the medulloblastomas (p < 0.05). Despite similar phenotypic features, a shared mechanism of tumori-genesis for retinoblastomas and the subgroup of medulloblastomas with photoreceptor differentiation could not be identified since all 17 medulloblastomas were found to express functional Rb protein, as indicated by positive nuclear immunoreactivity.

Original languageEnglish (US)
Pages (from-to)664-672
Number of pages9
JournalJournal of Neuropathology and Experimental Neurology
Issue number5
StatePublished - Sep 1995


  • Flexner-Wintersteiner rosette
  • IRBP
  • Medulloblastoma
  • Rb protein
  • Retinal S-antigen
  • Retinoblastoma
  • Rod-opsin

ASJC Scopus subject areas

  • General Medicine


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