Molecular Biomarker Testing in Advanced Breast Cancer: Current Landscape and Future Directions-US-104755_Unbranded Molecular Testing Webinar_mp4_10.21.25

Video Transcription

Video Summary

Dr. Crystal Whitmore presented on molecular biomarker testing in advanced breast cancer, focusing on the current landscape and future directions. Guidelines from NCCN and ASCO recommend comprehensive germline and somatic testing at metastatic diagnosis to guide targeted therapies. Key actionable biomarkers include PIK3CA, AKT1, P10 alterations, and ESR1 mutations, particularly prevalent in hormone receptor-positive, HER2-negative breast cancer. Testing methods consist of next-generation sequencing (NGS) and PCR-based assays, applied to tissue or circulating tumor DNA (ctDNA) from blood.<br /><br />PIK3CA, AKT1, and P10 pathway alterations drive tumor growth and contribute to therapy resistance, especially against endocrine treatments. While tissue biopsies are invasive and reflect single tumor sites, ctDNA testing provides a minimally invasive, real-time, comprehensive view of tumor heterogeneity and mutation status. ESR1 mutations, which mediate resistance to endocrine therapy, emerge in about 40% of patients following treatment and are best detected using ctDNA assays since they can predict relapse months before clinical progression.<br /><br />The multidisciplinary team, including pathologists, plays a crucial role in initiating timely molecular testing and interpreting results to personalize treatment and identify clinical trial candidates. Implementing reflex testing protocols and integrating ctDNA-based ESR1 mutation monitoring pose institutional challenges but offer opportunities for earlier therapeutic intervention and improved patient outcomes. Overall, molecular biomarker testing is essential for precision oncology in advanced breast cancer management.

Keywords

molecular biomarker testing

advanced breast cancer

PIK3CA mutations

AKT1 alterations

ESR1 mutations

circulating tumor DNA

next-generation sequencing

precision oncology