Breast cancers with high proliferation and low ER-related signalling have poor prognosis and unique molecular features with implications for therapy
Menée à partir de données d'expression génique portant sur 443 patientes atteintes d'un cancer du sein ER+/HER2- et ayant reçu une chimiothérapie néoadjuvante (avec ou sans pembrolizumab) ou un traitement endocrinien (avec ou sans palbociclib) puis menée à partir de données du projet "The Cancer Genome Atlas", cette étude examine les réponses thérapeutiques et les caractéristiques moléculaires des tumeurs présentant une prolifération cellulaire élevée et une faible signalisation associée aux récepteurs des estrogènes
Background : Luminal breast cancers with high proliferation (MKShi) and low ER-related signalling (ERSlo) have a poor prognosis. We investigated treatment responses and molecular features of MKShi/ERSlo tumours to inform potential therapies.
Methods : Gene expression data from patients who received neoadjuvant chemotherapy (NAC) without (MDACC, N = 199) or with pembrolizumab (I-SPY2, N = 40), or endocrine therapy (NET) without (POETIC, N = 172) or with palbociclib (NeoPalAna, N = 32) were analyzed to assess treatment response by MKS/ERS-subgroups. TCGA was used to assess the mutational landscape and biomarkers associated with palbociclib-resistance (Cyclin-E, RBsig, IRPR) and immunotherapy-response (TMB, TILs, T-cell inflamed) by MKS/ERS-subgroups.
Results : Compared to MKShi/ERShi tumours, MKShi/ERSlo tumours had higher pathological response rates to NAC (22% vs 8%, p = 0.06) but a higher recurrence risk (4-year metastasis-free survival 70% vs 94%, p = 0.01). MKShi/ERSlo tumours frequently harboured TP53 (34%) and PIK3CA (33%) mutations, and showed high expression of Cyclin-E, RBsig and IRPR, high TMB and elevated TIL and T-cell inflamed metagene expression. MKShi/ERSlo tumours retained high proliferation after NET with or without palbociclib but had higher pathological complete response rates when pembrolizumab was added to NAC (42% vs 21%, p = 0.07).
Conclusions : MKShi/ERSlo tumours have dismal outcomes and are enriched in chemotherapy-sensitive but ET- and palbociclib-resistant tumours. Biomarker analysis and clinical data suggest a potential role for immunotherapy in this group.
British Journal of Cancer , article en libre accès, 2023