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Molecular Analysis of PIK3CA in Metastatic Hormone Receptor-Positive Breast Cancer in Chile: Clinical and
Carla Araya1,2, Bárbara Mino1, Patricio Le Cerf3
1Clínica Alemana Facultad de Medicina, Universidad del Desarrollo, Santiago 7650567, Chile.
Abstract:
Breast cancer is the most common cancer among women and a leading cause of cancer-related deaths. PIK3CA gene mutations, which are often present in advanced HR+ breast cancer, can be targeted by alpelisib. However, data on PIK3CA mutations in Chile are limited. Here, we aim to assess the mutational status of PIK3CA in metastatic breast cancer tissues from Chilean patients and describe their clinicopathological characteristics and survival outcomes. We analyzed 102 formalin-fixed, paraffin-embedded metastatic breast cancer samples from 96 patients diagnosed at three Chilean hospitals between 2007 and 2023. PIK3CA mutations were identified using targeted sequencing, and clinicopathological data were collected. We evaluated associations between mutational status, clinicopathological features, and survival. The median age at diagnosis was 56 years. The most common metastatic sites were liver (29.4%), bone (17.6%), and lung/pleura (16.7%). Most patients were HR+ HER2- (83.3%), with 57.3% showing HER2-low status. PIK3CA mutations were present in 40.6% of patients, mainly in exons 7, 9, and 20. No significant associations were found between PIK3CA mutations and clinicopathological characteristics or survival. Our study reveals a high frequency of PIK3CA mutations in HR+ metastatic breast cancer, consistent with global data. The majority of mutations are targetable with alpelisib. The proportion of HER2-low status patients suggests potential benefits from novel HER2-targeted therapies. These findings highlight the need for routine molecular diagnostics in Chile to improve personalized treatment and address economic and access challenges.
Insights
A study found PIK3CA gene mutations in 40.6% of Chilean metastatic breast cancer patients, with most targetable by alpelisib. This highlights the need for molecular diagnostics in Chile for personalized breast cancer treatment.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Breast cancer is a leading cause of death in women globally.
- PIK3CA gene mutations are common in advanced hormone receptor-positive (HR+) HER2-negative breast cancer and are targets for alpelisib therapy.
- Limited data exists on PIK3CA mutation prevalence in Chilean breast cancer patients.
Purpose of the Study:
- To determine the frequency of PIK3CA gene mutations in metastatic breast cancer tissues from Chilean patients.
- To describe the clinicopathological characteristics and survival outcomes associated with PIK3CA mutations.
- To assess the potential for targeted therapies like alpelisib in this population.
Main Methods:
- Analysis of 102 metastatic breast cancer samples from 96 Chilean patients (2007-2023).
- Identification of PIK3CA mutations using targeted sequencing.
- Collection and evaluation of clinicopathological data and survival outcomes.
Main Results:
- PIK3CA mutations were identified in 40.6% of patients, primarily in exons 7, 9, and 20.
- The majority of patients (83.3%) were HR+ HER2-.
- 57.3% of patients had HER2-low status.
- No significant associations were found between PIK3CA mutational status and clinicopathological features or survival outcomes.
Conclusions:
- The high frequency of PIK3CA mutations in Chilean HR+ metastatic breast cancer patients aligns with global findings.
- Most identified PIK3CA mutations are potentially targetable with alpelisib.
- The prevalence of HER2-low status suggests potential benefits from novel HER2-targeted therapies.
- Routine molecular diagnostics are crucial in Chile to guide personalized breast cancer treatment and overcome access barriers.
