PTEN loss is not associated with trastuzumab resistance in metastatic breast cancer
Muharrem Kocar1, Emine Bozkurtlar, Ferhat Telli
1Department of Medical Oncology, Sanliurfa State Hospital, Sanliurfa, Turkey.
Purpose:
Although the clinical benefits of trastuzumab are well known, intrinsic or acquired resistance is a commonly encountered clinical condition. A potential resistance mechanism is aberrant downstream signal transmission due to loss of phosphatase and tensine homologue (PTEN). This study investigated the relationship between trastuzumab response and loss of PTEN in metastatic breast cancer patients.
Methods:
Patients with histologically confirmed human epidermal growth factor receptor 2 (HER2) positive metastatic breast cancer, who were treated with trastuzumab were enrolled into the study. PTEN expression was immunohistochemically evaluated.
Results:
The patient median age was 50 years. Of 38 patients, 6 (15.8%) showed PTEN loss. No statistically significant difference was found between trastuzumab response, overall survival (OS) and progression-free survival (PFS) and PTEN loss (p=0.538).
Conclusion:
The activation of phosphatidylinositol 3-kinase (PI3K) pathway resulting from PTEN loss was not found to be correlated with trastuzumab response and survival. PTEN loss should not lead to exclusion of patients from the potential to benefit from trastuzumab administration.
Insights
Loss of phosphatase and tensin homologue (PTEN) did not affect trastuzumab response in metastatic breast cancer patients. PTEN loss does not exclude patients from trastuzumab treatment benefits.
Area of Science:
- Oncology
- Molecular Biology
Background:
- Trastuzumab is a key therapy for HER2-positive metastatic breast cancer.
- Intrinsic or acquired resistance to trastuzumab remains a clinical challenge.
- Loss of phosphatase and tensin homologue (PTEN) is a potential resistance mechanism.
Purpose of the Study:
- To investigate the association between PTEN loss and trastuzumab response in metastatic breast cancer.
- To determine if PTEN loss impacts overall survival (OS) and progression-free survival (PFS).
Main Methods:
- Retrospective analysis of metastatic breast cancer patients treated with trastuzumab.
- Immunohistochemical evaluation of PTEN expression in tumor samples.
- Correlation analysis of PTEN loss with trastuzumab response, OS, and PFS.
Main Results:
- 38 patients were included, with a median age of 50.
- PTEN loss was observed in 6 patients (15.8%).
- No statistically significant difference in trastuzumab response, OS, or PFS was found between patients with and without PTEN loss (p=0.538).
Conclusions:
- PTEN loss, and subsequent phosphatidylinositol 3-kinase (PI3K) pathway activation, was not correlated with trastuzumab response or survival outcomes.
- PTEN loss should not be a criterion for excluding patients from trastuzumab therapy.
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