Prior systemic treatment increased the incidence of somatic mutations in metastatic breast cancer

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Understanding breast cancer biology is key for effective treatment strategies and identifying resistance mechanisms.
• Investigating the link between prior systemic therapy and the mutational landscape in metastatic breast cancer is critical.
• Identifying clinicopathological factors associated with common somatic mutations provides valuable insights.

Purpose of the Study:

• To explore the association between previous systemic therapy exposure and the mutational spectrum in metastatic breast cancer.
• To identify clinicopathological factors linked to frequent somatic mutations in breast cancer.
• To understand how systemic treatments influence the genetic profile of metastatic breast cancer.

Main Methods:

• Next-generation sequencing was used for hotspot molecular testing on archival tissues from metastatic breast cancer patients.
• Multivariate logistic models were employed to assess the relationship between mutation status and clinical variables.
• Variables showing significant differences in univariate analysis (P < 0.05) were included in multivariate models.

Main Results:

• Analysis included 922 patients with metastatic breast cancer.
• Previous systemic treatment was associated with significantly higher rates of TP53 and PIK3CA mutations (P < 0.001).
• This association was observed in multivariate analysis comparing patients with and without prior systemic treatment.

Conclusions:

• Systemic treatment exposure is an independent risk factor for elevated TP53 and PIK3CA mutation rates.
• Testing tumor samples after systemic therapy is important for accurate mutation assessment.
• Analyzing gene profiles in treatment-resistant tumors can reveal mechanisms of resistance.