In the management of early hormone receptor (HR)+, HER2-negative breast cancer, circulating tumor DNA (ctDNA) detection is an evolving yet promising diagnostic approach. We evaluated ctDNA detection using the personalized RaDaR assay in plasma samples from patients enrolled in the NeoRHEA clinical trial (NCT03065621), a single-arm, phase II study of neoadjuvant palbociclib and endocrine therapy administered over 4 months (four 28‑day cycles). Plasma samples were collected pre-treatment, after the first treatment cycle, prior to surgery, and one month post-surgery. At baseline, ctDNA positivity was detected in 55% of patients; however, this dropped to 5% during treatment and ctDNA became undetectable in all patients by one month post-surgery. CtDNA detection at baseline was higher in histological grade 3 tumors, lower in multifocal/multicentric tumors and higher in residual cancer burden (RCB) 3 tumors. Genomic analysis revealed MYC gene gains or amplifications were more frequent in ultrasound (US) responders, while PIK3CA gains were more common in US non-responders. Additionally, FAT1 losses were more frequently observed in patients with RCB 3. Our findings suggest that baseline ctDNA presence predicts poor response to neoadjuvant palbociclib and endocrine therapy, underscoring its potential as a biomarker to guide tailored therapeutic approaches in HR+/HER2-negative breast cancer.
Whole-exome sequencing (WES) analysis data from tumor tissues of 14 patients with T follicular helper cell lymphomas enrolled in a phase 2 trial of dasatinib for relapsed or refractory nodal disease.
