Abstract 3743
Background
The identification of HER2 overexpression in a subset of gastric cancer (GC) patients represents a significant step forward in unveiling the molecular complexity of this disease. The predictive and prognostic value of HER2 amplification in advanced HER2 inhibitor-treated GC patients has been investigated. However, its predictive value in early stage resectable patients remains unclear. In this study we interrogated the correlation between HER2 copy number (CN) and disease-free survival (DFS).
Methods
We enrolled 98 treatment-naïve resectable (stage I-III) Chinese GC patients with HER2 overexpression assessed using IHC. Capture-based targeted sequencing using a panel consisting of 41 gastrointestinal cancer -related genes was performed on FFPE samples. Furthermore, we also investigated the correlation between HER2 CN and DFS. This cohort had 81 males and 17 females, with a median age of 64. 12, 62 and 24 patients had diffuse, intestinal and mixed GC respectively.
Results
Of the 98 HER2-overexpressed patients assessed using IHC, 91 had HER2 CN amplification assessed using next-generation sequencing, achieving 93% concordance. In addition, 10 had concurrent HER2 missense mutations, including 4 with S310X. All patients except for two had at least one concurrent mutation. The most commonly seen concurrent mutations were TP53, EGFR and PIK3CA, occurring in 85%, 13% and 12% patients, respectively. Furthermore, 23 patients had mutations in EGFR, MET, PDGFRA or KIT, which may participate in the activation of bypass pathways. We also revealed that patients with concurrent TP53 (p = 0.05) or PI3KCA (p = 0.02) mutations were significantly older than patients without. Next, dichotomous analysis was performed to investigate the association between HER2 CN and DFS. Stage I patients did not undergo adjuvant chemotherapy and all stage II-III patients underwent adjuvant chemotherapy. Our study revealed that patients with high HER2 CN had a significantly shorter DFS than patients with low HER2 CN (p = 0.002).
Conclusions
We elucidated the mutation spectrum of HER2-amplified resectable Chinese GC patients and the association between HER2 CN and DFS. Our study revealed the predictive value of HER2 CN and allowed us to further stratify HER2-positive patients.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2840 - Effects of Aerobic and Resistance Exercise on Android:Gynoid Fat Ratio in Breast Cancer Survivors
Presenter: Christina Dieli-Conwright
Session: Poster Display session 2
Resources:
Abstract
869 - Impact of Education for Breast self examination in Rural Indian Women on Early Detection - results of POC study
Presenter: Sneha Parchuri
Session: Poster Display session 2
Resources:
Abstract
1951 - Breast cancer incidence and survival in renal transplant patients: 35-year experience
Presenter: Michalis Kontos
Session: Poster Display session 2
Resources:
Abstract
2017 - The changing landscape of breast cancer incidence after treatment for Hodgkin’s disease
Presenter: Amelia Benjamin
Session: Poster Display session 2
Resources:
Abstract
1780 - Number of deliveries as a prognostic factor in different breast cancer subtypes
Presenter: Anniina Jääskeläinen
Session: Poster Display session 2
Resources:
Abstract
4650 - Effects of supervised and adapted exercise program in the quality of life and strength of breast cancer survivors: MAMA MOVE Gaia trial
Presenter: Ana Joaquim
Session: Poster Display session 2
Resources:
Abstract
4962 - Study On the Socioeconomic and Clinical Factors Affecting the Proportion of Breast Conserving Surgery in Chinese Women Breast Cancer
Presenter: Jin Zhang
Session: Poster Display session 2
Resources:
Abstract
5451 - Clinical decision making and multidisciplinary team meetings (MDMs) in early breast cancer. Is the agreement between planned and applied therapeutic program?
Presenter: Marco Giavarra
Session: Poster Display session 2
Resources:
Abstract
888 - The value of genetic counselling in breast cancer genetic testing and clinical management
Presenter: Vicki Kiesel
Session: Poster Display session 2
Resources:
Abstract
4005 - Elderly patients in the Japanese Breast Cancer Registry
Presenter: Masataka Sawaki
Session: Poster Display session 2
Resources:
Abstract