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PIK3CA exon 20 mutations are associated with poor prognosis in breast cancer patients

Flavia R Mangone1, Irina G Bobrovnitchaia, Sibeli Salaorni

  • 1Departamento de Radiologia e Oncologia, Disciplina de Oncologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.

Clinics (Sao Paulo, Brazil)
|November 28, 2012
PubMed
Abstract

Insights

Phosphatidylinositol 3-kinase CA (PIK3CA) mutations are common in Brazilian breast cancer patients. PIK3CA exon 20 mutations correlate with poor survival and TP53 mutations, suggesting potential therapeutic biomarkers.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • The phosphatidylinositol 3-kinase/AKT pathway is crucial for cell growth and survival, and its dysregulation is implicated in cancer.
  • Mutations in the phosphatidylinositol 3-kinase CA (PIK3CA) gene, encoding the p110α subunit, are frequently found in various human tumors, including breast cancer.
  • The prevalence and clinical significance of PIK3CA mutations in Brazilian breast cancer patients remain underexplored.

Purpose of the Study:

  • To investigate the frequency and spectrum of PIK3CA mutations in Brazilian breast cancer patients.
  • To analyze the association between PIK3CA mutations and clinicopathological features, including TP53 mutations and patient survival.
  • To evaluate the potential of PIK3CA mutations as biomarkers for aggressive breast cancer and treatment response.

Main Methods:

  • PCR-SSCP and direct DNA sequencing were employed to detect PIK3CA mutations in exons 9 and 20.
  • Eighty-six sporadic breast cancer patients were analyzed for PIK3CA mutations.
  • Clinicopathological data, TP53 mutation status, and survival outcomes were correlated with PIK3CA mutation findings.

Main Results:

  • PIK3CA mutations were identified in 27% (23/86) of the breast tumors analyzed.
  • Hotspot mutations (E542K, E545K, H1047R) and novel mutations (I1022V, L1028S, R992X) were discovered in exons 9 and 20.
  • PIK3CA exon 20 mutations were significantly associated with poorer overall survival and the presence of TP53 mutations.

Conclusions:

  • PIK3CA mutations are prevalent in Brazilian breast cancer patients, indicating their importance in this population.
  • PIK3CA and TP53 mutations can co-occur, suggesting complex genetic alterations in breast cancer.
  • PIK3CA exon 20 mutations serve as potential biomarkers for identifying aggressive breast tumors and predicting response to PI3K pathway-targeted therapies.

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