American Association for Cancer Research
10780432ccr211810-sup-265943_3_supp_7412681_qzrtf7.pdf (1.81 MB)

Figure S5 from High FGFR1–4 mRNA Expression Levels Correlate with Response to Selective FGFR Inhibitors in Breast Cancer

Download (1.81 MB)
journal contribution
posted on 2023-03-31, 23:12 authored by Mònica Sánchez-Guixé, Cinta Hierro, José Jiménez, Cristina Viaplana, Guillermo Villacampa, Erika Monelli, Fara Brasó-Maristany, Zighereda Ogbah, Mireia Parés, Marta Guzmán, Judit Grueso, Olga Rodríguez, Mafalda Oliveira, Analía Azaro, Elena Garralda, Josep Tabernero, Oriol Casanovas, Maurizio Scaltriti, Aleix Prat, Rodrigo Dienstmann, Paolo Nuciforo, Cristina Saura, Mariona Graupera, Ana Vivancos, Jordi Rodon, Violeta Serra

Supplementary Figure 5. Relative expression levels of lucitanib-specific RTK targets and ligands in PDX and patient tumors. A) mRNA expression levels of 2544 genes detected by HTG in Pt325 samples (Pre-tt versus On-tt). Highlighted are some differentially expressed genes between both samples, including FGFR1. Data is log-2 transformed. B) and C) Relative mRNA levels of lucitanib-specific RTK targets or cognate ligands in PDX and patient tumors from the MTKI/FGFRi-treated patient cohort from Figure 3D, respectively.



Catalan Agency for Management of University and Research



FGFR1 amplification (FGFR1amp) is recurrent in metastatic breast cancer (MBC) and is associated with resistance to endocrine therapy and CDK4/6 inhibitors (CDK4/6is). Multi-tyrosine kinase inhibitors (MTKIs) and selective pan-FGFR inhibitors (FGFRis) are being developed for FGFR1amp breast cancer. High-level FGFR amplification and protein expression by IHC have identified breast cancer responders to FGFRis or MTKIs, respectively. Here, we used preclinical models and patient samples to identify predictive biomarkers to these drugs. We evaluated the antitumor activity of an FGFRi and an MTKI in a collection of 17 breast cancer patient–derived xenografts (PDXs) harboring amplification in FGFR1/2/3/4 and in 10 patients receiving either an FGFRi/MTKI. mRNA levels were measured on FFPE tumor samples using two commercial strategies. Proliferation and angiogenesis were evaluated by detecting Ki-67 and CD31 in viable areas by immunofluorescence. High FGFR1–4 mRNA levels but not copy-number alteration (CNA) is associated with FGFRi response. Treatment with MTKIs showed higher response rates than with FGFRis (86% vs. 53%), regardless of the FGFR1–4 mRNA levels. FGFR-addicted PDXs exhibited an antiproliferative response to either FGFRis or MTKIs, and PDXs exclusively sensitive to MTKI exhibited an additional antiangiogenic response. Consistently, the clinical benefit of MTKIs was not associated with high FGFR1–4 mRNA levels and was observed in patients previously treated with antiangiogenic drugs. Tailored therapy with FGFRis in molecularly selected MBC based on high FGFR1–4 mRNA levels warrants prospective validation in patients with CDK4/6i-resistant luminal breast cancer and in patients with TNBC without targeted therapeutic options.