PIK3CA exon 20 mutation is independently associated with a poor prognosis in breast cancer patients

Yuen Liang Lai, Bey Liing Mau, Wen Hsuan Cheng, Han Ming Chen, Hsi Hsiung Chiu, Chin Yuan Tzen

Research output: Contribution to journalArticlepeer-review

89 Citations (Scopus)


Background: Prognostic factors that could select breast cancer patients with poor survival, and influence clinical trials of targeted therapy, are needed. However, the reported observations regarding the impact of PI3KCA mutation on breast cancers are controversial. Methods: We analyzed exons 4, 7, 9, and 20 of PI3KCA on a series of 158 patients. Clinicopathological characteristics were correlated with the mutation data. Results: Among 152 patients who were available for follow-up (median follow-up time, 6.57 years), 26% had PIK3CA mutations, more than half of which occurred in exon 20. The five-year survival rate of patients with exon 20 mutations (46%) was significantly lower than that of patients without (75%) (p = 0.0054). Multivariate analysis showed that PIK3CA exon 20 mutations and nodal involvement were independent risk factors for overall survival. The relative risk of death in patients with PIK3CA exon 20 mutations was 2.881 (95% CI, 1.406-5.900; p = 0.0038). Conclusions: PIK3CA mutations are common in invasive ductal carcinomas of the breast. Our result suggests that PIK3CA exon 20 mutation is an independent risk factor for poor prognosis in breast cancer patients, indicating that differences in patient numbers with PIK3CA exon 20 mutations in study and control arms should be avoided in clinical trials of PI3K inhibitors.

Original languageEnglish
Pages (from-to)1064-1069
Number of pages6
JournalAnnals of Surgical Oncology
Issue number4
Publication statusPublished - Apr 2008


  • Breast cancer
  • PI3K
  • PIK3CA mutation
  • Prognosis

ASJC Scopus subject areas

  • Surgery
  • Oncology


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