Unraveling the clinicopathological and molecular changes induced by neoadjuvant chemotherapy and endocrine therapy in hormone receptor-positive/HER2-low and HER2-0 breast cancer

Abstract Background The characterization and comparison of gene expression (GE) and intrinsic subtypes (IS) changes induced by neoadjuvant chemotherapy (NACT) and endocrine therapy (NET) in hormone receptor-positive(HR+)/HER2-low vs. HR+/HER2-0 breast cancer (BC) has not been conducted so far. Most evidence on the association of HER2 status with pathologic responses and prognosis in HR+/HER2-negative BC is controversial and restricted to NACT-treated disease. Similarly, a temporal heterogeneity in HER2 status has been described only with NACT.Methods We retrospectively recruited a consecutive cohort of 186 patients with stage I-IIIB HR+/HER2-negative BC treated with neoadjuvant therapy (NAT). Available diagnostic biopsies and surgical samples were characterized for main pathological features, PAM50 intrinsic subtypes (IS) and risk-of-relapse (ROR)-P score, and GE. Associations with pathologic complete response (pCR), residual cancer burden (RCB)-0/I, event-free survival (EFS) and overall survival (OS) based on HER2 status were assessed. Pre/post pathologic/molecular changes were analyzed in matched samples.Results The HER2-low (62.9%) and HER2-0 (37.1%) cohorts did not differ significantly in main baseline features, treatments administered, breast conserving surgery (BCS), pCR and RCB-0/I rates, EFS and OS. NAT induced, regardless of HER2 status, a significant reduction of ER/PgR and Ki67, a downregulation of PAM50 proliferation- and luminal-related genes/signatures, an upregulation of selected immune genes and a shift towards less aggressive IS and lower ROR-P. Moreover, 25% of HER2-0 changed to HER2-low and 34% HER2-low became HER2-0. HER2 shifts were significant after NACT (p&lt;0.001), not NET (p=0.063), with consistentERBB2mRNA level dynamics. HER2 changes were not associated to EFS/OS.Conclusions HER2 status changes after NAT in ∼1/4 of cases, mostly after NACT. Targeted adjuvant strategies should be investigated accordingly. Molecular downstaging with current chemo/endocrine agents and immunotherapy should not rely on HER2 immunohistochemical levels in HR+/HER2-negative BC. Instead, HER2-low-targeted approaches should be explored to pursue more effective and/or less toxic dimensional downstaging.Highlights <jats:list list-type="order">Hormone receptor-positive (HR+)/HER2-low and HER2-0 breast cancer (BC) showed similar post-neoadjuvant surgical outcomes.Neoadjuvant therapy (NAT) induced a shift towards less aggressive subtypes and ROR-P classes regardless of HER2 status.All NAT strategies induced a downregulation of proliferation- and luminal biology-related genes, regardless of HER2 status.NAT induced changes in HER2 status, with a discordance rate of 34% and HER2-low showing higher instability than HER2-0.HER2 status at baseline, after surgery and its dynamics were not significantly associated to long-term outcomes..

Medienart:

Preprint

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

bioRxiv.org - (2024) vom: 02. Jan. Zur Gesamtaufnahme - year:2024

Sprache:

Englisch

Beteiligte Personen:

Schettini, Francesco [VerfasserIn]
Nucera, Sabrina [VerfasserIn]
Brasó-Maristany, Fara [VerfasserIn]
De Santo, Irene [VerfasserIn]
Pascual, Tomás [VerfasserIn]
Bergamino, Milana [VerfasserIn]
Galván, Patricia [VerfasserIn]
Conte, Benedetta [VerfasserIn]
Seguí, Elia [VerfasserIn]
García Fructuoso, Isabel [VerfasserIn]
Gómez Bravo, Raquel [VerfasserIn]
Rivera, Pablo [VerfasserIn]
Belén Rodríguez, Ana [VerfasserIn]
Martínez-Sáez, Olga [VerfasserIn]
Ganau, Sergi [VerfasserIn]
Sanfeliu, Esther [VerfasserIn]
González-Farre, Blanca [VerfasserIn]
Vidal, Maria [VerfasserIn]
Adamo, Barbara [VerfasserIn]
Cebrecos, Isaac [VerfasserIn]
Mension, Eduard [VerfasserIn]
Oses, Gabriela [VerfasserIn]
Jares, Pedro [VerfasserIn]
Vidal-Sicart, Sergi [VerfasserIn]
Mollà, Meritxell [VerfasserIn]
Muñoz, Montserrat [VerfasserIn]
Prat, Aleix [VerfasserIn]

Links:

Volltext [kostenfrei]

Themen:

570
Biology

doi:

10.1101/2023.12.27.23299114

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

XBI042021138