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Highly aggressive behavior of malignant rhabdoid tumor: a special reference to SMARCB1/INI1 gene alterations using

Kenichi Kohashi1, Yoshinao Oda, Hidetaka Yamamoto

  • 1Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812-8582, Japan.

Journal of Cancer Research and Clinical Oncology
|May 9, 2007
PubMed
Abstract

Insights

SMARCB1/INI1 gene alterations, including deletions and mutations, were found in 12 of 14 malignant rhabdoid tumor cases. This inactivation correlates with high RB protein hyperphosphorylation and the aggressive nature of MRT.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Malignant rhabdoid tumor (MRT) is characterized by homozygous inactivation of the SMARCB1/INI1 gene.
  • SMARCB1/INI1 normally regulates cell cycle progression via the p16INK4a-RB-E2F pathway.
  • Understanding SMARCB1/INI1 alterations is crucial for comprehending MRT pathogenesis.

Purpose of the Study:

  • To investigate SMARCB1/INI1 gene alterations using simple methods.
  • To analyze SMARCB1/INI1 protein expression.
  • To evaluate the phosphorylation status of the RB protein in MRT.

Main Methods:

  • Analysis of SMARCB1/INI1 gene alterations via quantitative real-time PCR and direct sequencing.
  • Immunohistochemical evaluation of SMARCB1/INI1 and RB protein expression.
  • Assessment of RB protein hyperphosphorylation in MRT cell lines and specimens.

Main Results:

  • Genetic alterations in SMARCB1/INI1 (deletions or mutations) were detected in 12 out of 14 MRT cases.
  • No SMARCB1/INI1 protein expression was observed in any of the investigated MRT cases.
  • A high rate of RB protein hyperphosphorylation was evident in 12 of 14 cases.

Conclusions:

  • Simple methods, particularly quantitative real-time PCR, are effective for analyzing SMARCB1/INI1 gene alterations.
  • SMARCB1/INI1 gene inactivation is a frequent event in MRT.
  • The observed SMARCB1/INI1 inactivation and RB hyperphosphorylation likely contribute to the aggressive clinical behavior of MRT.

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