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Updated: Oct 10, 2025
Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
Published on: June 8, 2019
Circulating PIK3CA mutation detection at diagnosis in non-metastatic inflammatory breast cancer patients
Violette Allouchery1, Anne Perdrix2,3, Céline Calbrix2,3
1Department of Medical Oncology, Centre Henri Becquerel, 1 Rue d'Amiens, 76038, Rouen Cedex 1, France. violette.allouchery@chb.unicancer.fr.
Abstract:
Inflammatory breast cancer (IBC) is an aggressive BC subtype with poor outcomes. A targetable somatic PIK3CA mutation is reported in 30% of IBC, allowing for treatment by PI3Kα-specific inhibitors, such as alpelisib. The aim of this study was to evaluate the detection rate of circulating PIK3CA mutation in locally-advanced IBC (LAIBC) patients harbouring a PIK3CA mutation on initial biopsy. This monocentric retrospective study was based on available stored plasma samples and tumour biopsies at diagnosis from all LAIBC patients treated with neo-adjuvant chemotherapy (NCT) between 2008 and 2018 at the Centre Henri Becquerel. PIK3CA mutations (E542K, E545K, H1047R/L) were assessed by droplet digital PCR (ddPCR) in plasma samples and tumoral tissue at diagnosis. A total of 55 patients were included. Overall, 14/55 patients (25%) had a PIK3CA mutation identified on baseline biopsy (H1047R = 8; H1047L = 3; E545K = 2; E542K = 1). Among them, 11 (79%) patients had enough DNA for circulating DNA analyses, and corresponding circulating PIK3CA mutations were found in 6/11 (55%). Among the 41 patients without PIK3CA mutations on biopsy, 32 (78%) had enough DNA for circulating DNA analysis, and no circulating PIK3CA mutation was identified. Our results revealed no prognostic or predictive value of PIK3CA mutations at the diagnosis of non-metastatic IBC but highlighted the prognostic value of the cfDNA rate at diagnosis. Our study showed that a corresponding circulating PIK3CA mutation was identified in 55% of LAIBC patients with PIK3CA-mutated tumours, while no circulating mutation was found among patients with PI3KCA wild-type tumours.
Insights
A PIK3CA mutation was detected in 55% of locally-advanced inflammatory breast cancer (IBC) patients using circulating tumor DNA. This finding is crucial for understanding treatment options for this aggressive cancer subtype.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Inflammatory breast cancer (IBC) is an aggressive subtype of breast cancer with poor prognosis.
- PIK3CA mutations are targetable in approximately 30% of IBC cases, offering a therapeutic avenue with PI3Kα-specific inhibitors like alpelisib.
- Accurate detection of these mutations is vital for personalized treatment strategies.
Purpose of the Study:
- To evaluate the detection rate of circulating PIK3CA mutations in locally-advanced IBC (LAIBC) patients with PIK3CA mutations identified in their initial tumor biopsy.
- To assess the correlation between circulating PIK3CA mutations and clinical outcomes in LAIBC.
Main Methods:
- A monocentric retrospective study analyzed plasma and tumor biopsy samples from LAIBC patients treated with neoadjuvant chemotherapy (NCT) between 2008 and 2018.
- PIK3CA mutations (E542K, E545K, H1047R/L) were quantified using droplet digital PCR (ddPCR) in both plasma and tumor tissue at diagnosis.
- Patient data, including mutation status and outcomes, were collected and analyzed.
Main Results:
- Of 55 patients, 14 (25%) had PIK3CA mutations in their tumor biopsy.
- Among these, 6 out of 11 (55%) with sufficient DNA had detectable circulating PIK3CA mutations in plasma.
- No circulating PIK3CA mutations were found in patients with wild-type tumors.
- PIK3CA mutations did not show prognostic or predictive value in non-metastatic IBC, but cfDNA levels did.
Conclusions:
- A corresponding circulating PIK3CA mutation was identified in 55% of LAIBC patients with PIK3CA-mutated tumors.
- The detection of circulating PIK3CA mutations may aid in monitoring and understanding treatment response in IBC.
- Further research is warranted to explore the clinical utility of circulating tumor DNA in managing IBC.
