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

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>=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.

Reliability and Discriminant Validity of HER2 Gene Quantification and Chromosome 17 Aneusomy Analysis by Real-Time PCR in Primary Breast Cancer

There is an increasing demand for the evaluation of HER2 status in breast cancer. In this study, sections from fixed tissues and triton extracts of tissue homogenates were obtained from 163 malignant breast tumors and analyzed in parallel using immunohistochemistry combined with fluorescence in situ hybridization, as gold standard tests, and an ELISA test (c-erbB2/c-neu Rapid Format ELISA, Oncogene Research Products, USA). Tumor DNA was employed to evaluate two quantitative PCR methods: the HER2/neu DNA Quantification Kit (Roche Diagnostics GmbH, Germany), which uses the gastrin chromosome 17 reference gene, and our recently developed Oncolab qPCR assay, where both a chromosome 17 gene (somatostatin receptor type II (SSTR2)) and a non-chromosome 17 reference gene (glyceraldehyde-3-phosphate deshydrogenase (GAPDH)) were used to detect an increase in HER2 gene copy number and to evaluate the aneusomy of chromosome 17, respectively. By IHC/FISH and ELISA, HER2 was overexpressed in 27 (16.6%) and 24 (14.7%) samples, respectively. With the Roche and Oncolab qPCR assays, 29 (17.8%) samples showed a ratio of HER2/gastrin ≥2.0 and 26 (16.0%) showed a ratio of HER2/SSTR2 ≥ 2.0, respectively. In samples presenting HER2/SSTR2 <2.0 and HER2/GAPDH ≥2.0, which was indicative of a chromosome 17 polysomy, we observed a modest increase in HER2 protein expression. Complete agreement between the four methods for HER2 status determination was obtained for 154 (94.5%) samples. Overall, these results demonstrate that quantitative PCR is a reliable method for analyzing HER2 status and chromosome 17 polysomy.

Guidelines for time-to-event end point definitions in breast cancer trials: results of the DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials)†

BACKGROUND

Using surrogate end points for overall survival, such as disease-free survival, is increasingly common in randomized controlled trials. However, the definitions of several of these time-to-event (TTE) end points are imprecisely which limits interpretation and cross-trial comparisons. The estimation of treatment effects may be directly affected by the definitions of end points. The DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials) aims to provide recommendations for definitions of TTE end points. We report guidelines for randomized cancer clinical trials (RCTs) in breast cancer.

PATIENTS AND METHODS

A literature review was carried out to identify TTE end points (primary or secondary) reported in publications of randomized trials or guidelines. An international multidisciplinary panel of experts proposed recommendations for the definitions of these end points based on a validated consensus method that formalize the degree of agreement among experts.

RESULTS

Recommended guidelines for the definitions of TTE end points commonly used in RCTs for breast cancer are provided for non-metastatic and metastatic settings.

CONCLUSION

The use of standardized definitions should facilitate comparisons of trial results and improve the quality of trial design and reporting. These guidelines could be of particular interest to those involved in the design, conducting, reporting, or assessment of RCT.

Morphological and immunohistochemical study of ovarian and tubal dysplasia associated with tamoxifen

Ovarian epithelial dysplasia was initially described in material from prophylactic oophorectomies for BReast CAncer gene (BRCA) mutation. Similar histopathological abnormalities have been revealed after ovulation stimulation. Given that tamoxifen (TAM) has a clomid-like effect and is sometimes used to induce ovulation, we studied the morphological features and immunohistochemical expression patterns of neoplasia-associated markers in adnexectomies previously exposed to TAM for breast cancer. We blindly reviewed 173 histopathological slides of adnexectomies according to three groups – oophorectomies associated with TAM exposure (n=42), oophorectomies associated with clomiphene exposure (n=15) and a spontaneously fertile non cancerous control group (n=116). Morphological features (with an ovarian and tubal dysplasia scoring system) and immunohistochemical expression patterns of Ki-67, p53 and Aldehyde dehydrogenase 1 (ALDH1 is an enzyme significantly associated with earlystage ovarian cancer) were evaluated and correlated. Mean tubal dysplasia score was significantly higher in the TAM group and clomiphen group than in controls (respectively 7.8 vs 3.5, P<0.007 and 6.8 vs 3.5, P=0.008). There is no statistical difference for the ovarian score in TAM group in comparison with the control group whereas we found a significant score for clomiphen group (6.5, P=0.009). Increased ALDH1 expression was observed in the two exposed group whereas expression patterns of Ki67 and p53 were moderate. Interestingly, ALDH1 expression was low in non-dysplastic epithelium, high in dysplasia, and constantly low in the two carcinoma.

Furthemore, we confirm our previous results showing that ALDH1 may be a useful tissue biomarker in the subtle histopathological diagnosis of tubo-ovarian dysplasia.

A nomogram predictive of non-sentinel lymph node involvement in breast cancer patients with a sentinel lymph node micrometastasis

PURPOSE

Predictive factors of non-sentinel lymph node (NSN) involvement at axillary lymph node dissection (ALND) have been studied in the case of sentinel node (SN) involvement, with validation of a nomogram. This nomogram is not accurate for SN micrometastasis. The purpose of our study was to determine a nomogram for predicting the likelihood of NSN involvement in breast cancer patients with a SN micrometastasis.

METHODS

We collated 909 observations of SN micrometastases with additional ALND. Characteristics of the patients, tumours and SN were analysed.

RESULTS

Involvement of SN was diagnosed 490 times (53.9%) with standard staining (HES) and 419 times solely on immunohistochemical analysis (IHC) (46.1%). NSN invasion was observed in 114 patients (12.5%), whereas 62.3% (71) had only one NSN involved and 37.7% (43) two or more NSN involved. In multivariate analysis, significant predictive factors were: tumour size (pT stage < or = 10 mm or >11 and < or = 20 or >20 mm [odds ratio (OR) 2.1 and 3.43], micrometastases detected by HES or IHC [OR 1.64], presence or absence of lymphovascular invasion (LVI) [OR 1.76], tumour histological type mixed or not [OR 2.64]. The rate and probability of NSN involvement with the model are given for 24 groups, with a representation by a nomogram.

CONCLUSION

One group, corresponding to 10.1% of the patients, was associated with a risk of NSN involvement of less than 5%, and five groups, corresponding to 29.8% of the patients, were associated with a risk < or = 10%. Omission of ALND could be proposed with minimal risk for a low probability of NSN involvement.