240PD - Comprehensive Genomic Profiling of Primary and Metastatic CDH1 Mutated Classic and Pleomorphic Invasive Lobular Breast Carcinomas Reveals Markers o...

Date 10 September 2017
Event ESMO 2017 Congress
Session Breast cancer, metastatic
Topics Breast Cancer, Metastatic
Breast Cancer
Personalised Medicine
Presenter Jeffrey Ross
Citation Annals of Oncology (2017) 28 (suppl_5): v74-v108. 10.1093/annonc/mdx365
Authors J.S. Ross1, L.M. Gay2, J.A. Elvin3, J. Suh3, J. Vergilio3, S. Ramkissoon3, E. Severson3, S. Daniel3, G.M. Frampton3, D. Fabrizio3, A.B. Schrock4, S.M. Ali3, V.A. Miller3, P. Stephens5, J. Chung2
  • 1Pathology, Albany Medical Center, 12208 - Albany/US
  • 2Pathology, Foundation Medicine, 02141 - Cambridge/US
  • 3R & D, Foundation Medicine, 02141 - Cambridge/US
  • 4Clinical Development, Foundation Medicine, MA 02141 - Cambridge/US
  • 5R & D, Foundation Medicine, MA 02141 - Cambridge/US

Abstract

Background

Although invasive lobular breast cancer (ILC) is typically combined with the far more frequent ductal disease for clinical trials and research studies. We queried whether classic (CILC) and its uncommon pleomorphic variant (PILC) featured unique genomic alterations (GA) which could influence therapy for patients with relapsed and refractory disease.

Methods

From a series of 10,784 invasive breast carcinomas DNA was extracted from 40 µm of FFPE sections of 454 (4%) CDH1 mutated ILC including 428 classic (CILC) (94%) and 26 pleomorphic (PILC) (6%) subtypes. CGP was performed on hybridization-captured, adaptor ligation-based libraries (mean coverage depth >600X) for up to 315 cancer-related genes. Total mutational burden (TMB) was determined on 1.2 Mbp of sequenced DNA.

Results

Median age at 63 years was similar for both CILC and PILC (see Table). Clincal ER+ status (p) was higher in CILC and HER2+ status was higher in PILC (P 

Conclusions

Both CILC and PILC show differences in GA in pre-treatment primary vs metastatic lesions in important genes such as ESR1 and ERBB2 likely reflecting the impact of primary therapies. Relapsed CILC is more often driven by ESR1 GA and PILC by ERBB2 GA. Both the CILC and PILC groups have subsets with high TMB, more frequent in PILC, indicating potential for immunotherapies for these patients.

Clinical trial identification

Legal entity responsible for the study

Jeffrey S Ross

Funding

None

Disclosure

J.S. Ross, V.A. Miller, P. Stephens: Employee, leader and owns stock in Foundation Medicine. L.M. Gay, J.A. Elvin, J-A. Vergilio, S. Ramkissoon, E. Severson, S. Daniel, G.M. Frampton, D. Fabrizio, A.B. Schrock, S.M. Ali, J. Chung, J. Suh: Employee and owns stock in Foundation Medicine.