Accumulation of wild-type p53 in astrocytomas is associated with increased p21 expression

Yasuhiro Ono, Takashi Tamiya, Tomotsugu Ichikawa, Kengo Matsumoto, Tomohisa Furuta, Takashi Ohmoto, Kosuke Akiyama, Shuji Seki, Keisuke Ueki, David N. Louis

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33 Citations (Scopus)

Abstract

Approximately one quarter of human astrocytomas show immunohistochemical positivity for p53 protein but lack p53 gene mutations, which could reflect either an accumulation of wild-type p53 protein or an inadequate sensitivity of mutation detection. Since wild-type p53 up-regulates p21 expression, increased p21 expression in those astrocytomas with p53 accumulation in the absence of mutations would argue that the protein was wild type in these tumors. We therefore compared p21 expression with p53 gene and protein status in 48 primary human astrocytomas. Single-strand conformation polymorphism analysis and direct sequencing of the p53 gene showed mutations in 11 tumors (22.9%), while immunohistochemistry revealed positive staining in 19 cases (39.6%). Those tumors with p53 immunopositivity in the absence of p53 mutation had significantly increased p21 expression when compared to either mutant p53 or p53 immunonegative cases. Neither p53 nor p21 status correlated with proliferation indices, as assessed by Ki-67 immunohistochemistry. These results support the hypotheses that functionally wild-type p53 accumulates in some astrocytomas, and that alternative cell cycle checkpoints (such as the p16 pathway) may be more important than p21 in regulating proliferation in astrocytomas.

Original languageEnglish
Pages (from-to)21-27
Number of pages7
JournalActa neuropathologica
Volume94
Issue number1
DOIs
Publication statusPublished - Jul 1 1997

Keywords

  • Astrocytoma
  • Immunohistochemistry
  • Single-strand conformation polymorphism
  • p21
  • p53

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

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    Ono, Y., Tamiya, T., Ichikawa, T., Matsumoto, K., Furuta, T., Ohmoto, T., Akiyama, K., Seki, S., Ueki, K., & Louis, D. N. (1997). Accumulation of wild-type p53 in astrocytomas is associated with increased p21 expression. Acta neuropathologica, 94(1), 21-27. https://doi.org/10.1007/s004010050667