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Expression of cyclin kinase inhibitor p21/WAF1 protein in pituitary adenomas: correlations with endocrine activity,

H Hiyama1, O Kubo, T Kawamata

  • 1Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Japan.

Acta Neurochirurgica
|July 12, 2002
PubMed

Insights

p21/WAF1 expression in pituitary adenomas correlates with endocrine activity, not cell proliferation. Cytoplasmic p21/WAF1 may confer resistance to DNA-damaging agents like radiation.

Area of Science:

  • Endocrinology
  • Oncology
  • Cell Biology

Background:

  • p21/WAF1 (also known as CDKN1A) is a key cell cycle inhibitor involved in cell cycle arrest and differentiation.
  • Its role in pituitary adenomas, particularly concerning endocrine activity and proliferation, requires further elucidation.

Purpose of the Study:

  • To investigate the expression of p21/WAF1 in pituitary adenomas.
  • To correlate p21/WAF1 expression with endocrine activity and cell proliferation markers.
  • To explore the potential implications of p21/WAF1 expression in treatment resistance.

Main Methods:

  • Immunohistochemical assessment of p21/WAF1 expression in 47 pituitary adenoma cases.
  • Evaluation of cell proliferation using the MIB-1 antibody (Ki-67 antigen).
  • Double staining techniques to identify co-expression with pituitary hormones (GH, PRL).

Main Results:

  • p21/WAF1 was positive in 24/26 functioning adenomas and negative in 14/21 non-functioning adenomas.
  • No correlation was found between p21/WAF1 positivity and the MIB-1 proliferation index.
  • Co-expression of p21/WAF1 with GH or PRL was observed in functioning adenomas.

Conclusions:

  • p21/WAF1 expression in pituitary adenomas is linked to endocrine activity, not cell proliferation.
  • Cytoplasmic p21/WAF1 may contribute to resistance against DNA-damaging agents, potentially impacting therapeutic strategies.

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