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PIK3CA mutations in breast cancer are associated with poor outcome

Shao Ying Li1, Minna Rong, Fabienne Grieu

  • 1School of Surgery and Pathology, University of Western Australia, Nedlands, Australia.

Breast Cancer Research and Treatment
|December 1, 2005
PubMed

Insights

Frequent PIK3CA mutations in breast cancer are linked to larger tumors and poorer survival, especially in estrogen receptor-positive or non-amplified erbB2 cases. These findings highlight PIK3CA as a key factor in breast cancer progression.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • The phosphatidylinositol-3-kinase (PI3K)-AKT pathway is crucial in cancer development.
  • Somatic mutations in PIK3CA, a PI3K subunit, are common across various cancers.

Purpose of the Study:

  • To investigate the frequency of PIK3CA mutations in primary human breast tumors.
  • To determine the association of PIK3CA mutations with pathological features and patient survival.

Main Methods:

  • Screening of 250 primary human breast tumors for PIK3CA mutations.
  • Analysis of mutation frequency in C2, helical, and kinase domains.
  • Correlation of mutations with tumor size, estrogen receptor status, and erbB2 amplification.

Main Results:

  • PIK3CA mutations were found in 35% (88/250) of breast tumors.
  • Mutations were significantly associated with larger tumor size (p = 0.004) and positive estrogen receptor status (p = 0.008).
  • Patients with PIK3CA mutations exhibited significantly worse survival (p = 0.004), particularly those with positive estrogen receptor or non-amplified erbB2 (p = 0.002).

Conclusions:

  • PIK3CA mutations are frequent in breast cancer and correlate with adverse pathological features.
  • PIK3CA mutation is an independent predictor of worse survival in breast cancer patients, especially those with non-amplified erbB2.
  • Targeting the PI3K pathway may offer therapeutic strategies for specific breast cancer subtypes.

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