PTEN deficiency as a predictive biomarker of resistance to HER2-targeted therapy in advanced gastric cancer

Xianglan Zhang, Ji Soo Park, Kyu Hyun Park, Ki Hyang Kim, Minkyu Jung, Hyun Cheol Chung, Sun Young Rha, Hyo Song Kim

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27 Citations (Scopus)

Abstract

Background: To investigate the role of the phosphoinositide 3-kinase (PI3K) pathway activation in human epidermal growth factor receptor 2 (HER2)-targeted therapy. Methods: We evaluated the predictive roles of PI3K, catalytic alpha (PIK3CA), and phosphatase and tensin homolog (PTEN) in HER2-based therapy (either trastuzumab or lapatinib). PTEN expression and PIK3CA mutation were analyzed using immunohistochemistry and pyrosequencing. Results: Forty-eight patients received trastuzumab (n = 39) or lapatinib (n = 9) combination chemotherapy. PTEN loss was found in 47.9% (n = 23), but no PIK3CA mutations were identified. Twenty-six (54.1%) patients responded to HER2-based therapy, without a significant difference between patients with PTEN loss and those without (52.2 vs. 56.0%). Among the patients with responsive disease, time to best response did not differ by PTEN status, but the duration of response was significantly shorter for patients with PTEN loss (median 4.2 vs. 6.1 months, p = 0.04). In addition, patients with PTEN loss had a significantly shorter progression-free survival time (median 4.9 vs. 7.3 months, p = 0.047). Conclusions: PTEN deficiency is an important predictive marker for early resistance to HER2 inhibitor treatment in gastric cancer patients. This finding may be useful for the development of drug combinations and identification of patients who need a modified treatment strategy.

Original languageEnglish
Pages (from-to)76-85
Number of pages10
JournalOncology (Switzerland)
Volume88
Issue number2
DOIs
Publication statusPublished - 2015 Apr 20

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All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

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