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Pharmacogenomic profiling of the PI3K/PTEN-AKT-mTOR pathway in common human tumors

Guang Xu1, Wanghai Zhang, Paula Bertram

  • 1Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.

International Journal of Oncology
|March 11, 2004
PubMed

Insights

Targeting the mammalian target of rapamycin (mTOR) pathway shows promise for cancer therapy. This study identified predictive markers for patient sensitivity to mTOR inhibitors across common human tumors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Biochemistry

Background:

  • The mammalian target of rapamycin (mTOR) pathway regulates protein synthesis and is crucial in cancer progression.
  • mTOR inhibition via rapamycin analogues demonstrates anti-cancer activity in preclinical and early clinical studies.
  • Identifying predictive biomarkers for mTOR inhibitor sensitivity is critical for clinical application.

Purpose of the Study:

  • To evaluate the expression of key PI3K/PTEN/AKT/mTOR pathway components in common human tumors.
  • To assess the coordinated expression of these signaling proteins.
  • To model tumor sensitivity to mTOR inhibition based on cellular markers.

Main Methods:

  • Immunohistochemistry was performed on tissue arrays from 124 tumors across 8 common types.
  • Expression levels of mTOR, p70 S6 kinase 1 (S6K1), 4E-BP1, PTEN, and AKT were analyzed.
  • Statistical correlation and predictive modeling were used to assess pathway component relationships and sensitivity.

Main Results:

  • Variable expression of PI3K/PTEN/AKT/mTOR pathway proteins was observed across tumor types.
  • Phospho-AKT (p-AKT) and phospho-S6K1 (p-S6K1) showed significantly correlated expression (rs=0.51, p<0.001).
  • A model predicting sensitivity based on low PTEN, high p-AKT, and high p-S6K1 identified 26% of tumors as potentially sensitive.

Conclusions:

  • This is the first study to report on the PI3K/PTEN/AKT/mTOR pathway in common human tumors and their coordinated protein expression.
  • The findings provide a framework for selecting patients for targeted mTOR inhibitor clinical trials.
  • Predictive markers for mTOR inhibitor sensitivity can guide future therapeutic strategies in oncology.

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