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Targeting the PI3K/AKT/mTOR pathway: biomarkers of success and tribulation

Taofeek K Owonikoko1, Fadlo R Khuri

  • 1From the Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA.

American Society of Clinical Oncology Educational Book. American Society of Clinical Oncology. Annual Meeting
|May 30, 2013
PubMed

Insights

Targeted therapies inhibiting the PI3K/AKT/mTOR pathway show promise for cancer treatment. Biomarkers, including protein and genetic markers, can identify patients most likely to benefit from these treatments.

Area of Science:

  • Oncology
  • Molecular Biology
  • Pharmacology

Background:

  • The Phosphoinositide 3-kinase/Protein Kinase B/Mammalian Target of Rapamycin (PI3K/AKT/mTOR) pathway is a critical regulator of cell growth and survival, frequently dysregulated in human cancers.
  • Approved mTOR inhibitors like everolimus and temsirolimus demonstrate efficacy in advanced renal, breast, and pancreatic cancers.
  • However, suboptimal patient benefit necessitates improved patient selection strategies for PI3K/AKT/mTOR pathway-targeted therapies.

Purpose of the Study:

  • To review the biological rationale and clinical utility of protein and genetic biomarkers for patient stratification in PI3K/AKT/mTOR pathway-targeted cancer therapy.
  • To highlight the development and validation of biomarkers that predict response to PI3K/AKT/mTOR inhibitors.

Main Methods:

  • Review of preclinical and clinical studies investigating the PI3K/AKT/mTOR pathway in cancer.
  • Analysis of protein-based biomarkers (e.g., phosphorylated S6, AKT, eIF4e) and genetic biomarkers (e.g., PIK3CA mutations, PTEN loss, TSC1/TSC2 mutations, PIK3CA-GS profile).
  • Evaluation of biomarker-driven patient selection strategies for mTOR inhibitors.

Main Results:

  • Altered PI3K/AKT/mTOR signaling underlies oncogenesis and influences treatment response.
  • Protein biomarkers reflect pathway activation, while genetic biomarkers identify specific pathway alterations.
  • Emerging data support the use of these biomarkers to identify patients likely to respond to targeted agents.

Conclusions:

  • Protein and genetic biomarkers hold significant promise for personalizing PI3K/AKT/mTOR inhibitor therapy in cancer.
  • Biomarker-guided selection can optimize treatment efficacy and improve outcomes for patients with advanced cancers.
  • Further validation and integration of these biomarkers into clinical practice are warranted.

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