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Phosphatidylinositol 3-kinase pathway activation in breast cancer brain metastases

Barbara Adamo1, Allison M Deal, Emily Burrows

  • 1Department of Medicine, Division of Hematology-Oncology, CB 7305, University of North Carolina, Chapel Hill, NC 27599, USA.

Breast Cancer Research : BCR
|December 3, 2011
PubMed
Abstract

Insights

The phosphatidylinositol 3-kinase (PI3K) pathway is active in most breast cancer brain metastases (BCBMs). While PI3K pathway markers didn't impact overall survival, PTEN loss correlated with shorter recurrence times and poorer survival in triple-negative BCBMs.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Metastasis

Background:

  • The activation status of the PI3K pathway in breast cancer brain metastases (BCBMs) is largely unknown.
  • Understanding PI3K pathway activity is crucial for developing targeted therapies for BCBMs.
  • This study investigates PI3K pathway markers (p-AKT, p-S6, PTEN) in BCBMs.

Purpose of the Study:

  • To determine the activation status of the PI3K pathway in BCBMs.
  • To assess the association between PI3K pathway markers and survival outcomes (overall survival, survival after BCBMs, time to distant recurrence, time to BCBMs).
  • To analyze PI3K pathway activation in triple-negative BCBMs.

Main Methods:

  • Immunohistochemistry was used to assess p-AKT, p-S6, and PTEN expression in 52 BCBMs and 12 matched primary breast cancers.
  • Patients were categorized into subtypes: hormone receptor (HR)+/HER2-, HER2+, and triple-negative (TNBC).
  • Survival analyses were performed using Cox models and Kaplan-Meier curves.

Main Results:

  • The PI3K pathway was active in most BCBMs, with high expression of p-AKT (75%) and p-S6 (69%), and frequent PTEN loss (25%).
  • PTEN loss was more prevalent in triple-negative BCBMs.
  • While PI3K pathway markers were not associated with overall survival or survival after BCBMs, PTEN loss correlated with shorter time to distant and brain recurrence, and poorer overall survival in TNBC patients.

Conclusions:

  • The PI3K pathway is frequently active in BCBMs across subtypes, suggesting it as a potential therapeutic target.
  • PTEN loss is a significant factor associated with recurrence and survival in specific BCBM subtypes, particularly TNBC.
  • Targeting the PI3K pathway may offer a promising strategy for BCBM patients with limited treatment options.

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