Abstract PD4-10: FGFR1 / ZNF217 copy numbers and outcome in patients with node positive, HR+/Her2- early breast cancer: A genomic analysis of PACS04 trial
Authors: Andre F , Penault Llorca F , Carene D , Roche H , Delaloge S , Lacroix L , Scott V , Richon C , Lacroix-Ticrit M , Lemonnier J , Michiels S 
Published: February 2018

Purpose: There is a need to identify which patients present a high risk of relapse after optimal adjuvant therapies, in order to better define which population of early breast cancer patients is eligible to new drugs. Previous studies have shown that gene copy numbers drive breast cancer progression. In the BIG1-98 trial, FGFR1 (8p11) and ZNF217 (20q13) amplifications were associated with poor outcome in patients with HR+/Her2- early breast cancers. In the present study, we aim to validate these findings using retrospective analysis of samples prospectively collected in a randomized trial (PACS04).

Patients and methods: Tumor DNA was extracted from FFPE samples obtained from patients included in PACS04 trial. This trial compared FEC to ED75 in patients with node positive, early breast cancer and included 3000 patients between 2001 and 2004. The biomarker study focuses on HR+/Her2- breast cancer. 500 samples were collected and hybridization was performed on 390. DNA copy numbers were assessed on 900 genes using Oncoscan FFPE assay kit. Prognostic value of FGFR1 (8p11) and ZNF217 (20q13) copy numbers was assessed in a Cox model that included prognostic parameters. Prognostic value was assessed using CNA as continuous variable, and with a predefined cut-off (CN&gt;=3). Metastases-free survival (MFS) was chosen as endpoint for this biomarker study.

Results: Tumor copy numbers alterations were obtained in 390 patients with HR+/Her2-, node positive, early breast cancer. 31% of the patients presented more than 3 lymph node involved, and 25% a poorly differenciated tumor. The median tumor size was 20 mm. 120 (30%) and 112 (28%) patients presented FGFR1 and/or ZNF217 gene gain with a cut-off for amplification predefined at 3 copies. When assessed as continuous variable, FGFR1 (HR: 1.02, 95%CI:1.007-1.04, p=0.0045) and ZNF217 (HR: 1.011, 95%CI:1.003-1.01, p=0.006) copy numbers were associated with MFS. The 10 years MFS rates were 68% (95%CI: 59-78%) and 85% (95%CI: 81-91%) in patients with FGFR1-gained and FGFR1-normal tumors respectively (HR: 2.51, 95%CI:1.56-4.01, p=0.0001). The 10 years MFS rates were 72% (95%CI:65%-83%) and 83% (95%CI: 77-87%) in patients with ZNF217-gained and ZNF217-normal tumors (HR: 1.79, 95%CI:1.12-2.86, p=0.013). In a multivariate analysis, FGFR1-gain (HR: 2.45, 95%CI:1.42-4.22, p=0.0012) and ZNF217-gain (HR:1.78, 95%CI:1.00-3.17, p=0.049) were associated with a higher likelihood of metastases and/or death. The 10 MFS rate was 88% (95%CI: 83-94%) for patients who presented FGFR1- and ZNF217-normal tumor (n=191), and 71% (95%CI: 66-76%) in patients presenting FGFR1 and/or ZNF217 gene gain.

Conclusion: Using samples prospectively collected in a randomized trial, this study validates the prognostic value of FGFR1- and ZNF217- copy numbers in patients who present HR+/Her2- early breast cancer. Exploratory analyses on copy number alterations, together with targeted sequencing are ongoing and will be presented.

Citation Format: Andre F, Penault Llorca F, Carene D, Roche H, Delaloge S, Lacroix L, Scott V, Richon C, Lacroix-Ticrit M, Lemonnier J, Michiels S. FGFR1 / ZNF217 copy numbers and outcome in patients with node positive, HR+/Her2- early breast cancer: A genomic analysis of PACS04 trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-10.