Abstract 5737
Background
HER2 breast cancer status determines patients’ eligibility for targeted therapy. HER2 level of amplification is associated with a better response to anti-HER2 therapy. Benefit of anti-HER2 therapy for equivocal cases remains debated.
Methods
We aimed to better characterize HER2-equivocal breast cancers by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) according to 2018 ASCO/CAP guidelines using PAM50 gene expression-based molecular subtyping and to investigate genome-wide copy number alterations of these cases. PAM50 (nCounter assay; Nanostring) was performed on RNA from FFPE samples of 60 HER2-equivocal cases. These cases were subsequently analyzed by Agilent 60-mer oligonucleotide microarrays for array-based comparative genomic hybridization (aCGH).
Results
The 60 HER2-equivocal cases were classified as Luminal B in 31 cases (52%), HER2-Enriched in 14 cases (23%), Luminal A in 13 cases (22%) and Basal-like in 2 cases (3%) using PAM50. By IHC, 52 cases (87%) were ER+, 43 (72%) were also PgR+, 40 (67%) were grade III and 45 (75%) showed a high Ki67 > 20%. With aCGH, 23 cases (38%) presented chr 17q large copy number gain, 14 (23%) showed segmental copy number gain including HER2, 10 (17%) showed HER2 amplification, one (2%) showed a large copy number loss and 12 cases (20%) didn’t show any copy number alteration of the chr 17. Out of the 14 PAM50 HER2-Enriched cases, only 5 showed HER2 genomic amplification (Table). In total, 14 cases (23%) were discordant between molecular classification and genomic alteration status of the chr 17.Table:
260P
Genomic alterations of chromosome 17 | Basal- like | HER2- Enriched | Luminal A | Luminal B | Total |
---|---|---|---|---|---|
HER2 amplified | 0 | 5 | 2 | 3 | 10 |
Large copy number gain | 0 | 1 | 5 | 17 | 23 |
Segmental copy number gain | 2 | 5 | 4 | 3 | 14 |
No alteration | 0 | 3 | 2 | 7 | 12 |
Large copy number loss | 0 | 0 | 0 | 1 | 1 |
Total | 2 | 14 | 13 | 31 | 60 |
Conclusions
Using PAM50, the majority of HER2-equivocal cases were classified as Luminal tumors (Luminal B 52% and A 22%) and harbored mostly at the genomic level chr 17 segmental or large copy number gains. As there is no evidence of benefit of anti-HER2 therapy in these cases, it emphasizes the need of genomic status determination of HER2-equivocal cases.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Anne Vincent-Salomon.
Funding
Has not received any funding.
Disclosure
P. Morel: Full / Part-time employment: Nanostring. H.A. Brauer: Full / Part-time employment: Nanosting. A. Vincent-Salomon: Advisory / Consultancy, Consulting fees: Roche; Advisory / Consultancy, Consulting fees: AstraZeneca; Non-remunerated activity/ies, Contracted Research: Nanostring. All other authors have declared no conflicts of interest.
Resources from the same session
1309 - Quantifying the Effects of the Korean National Cancer Screening Program on Cervical Cancer Mortality
Presenter: Nhung Bui
Session: Poster Display session 2
Resources:
Abstract
1346 - Spread of tumor and adverse events after modified radical hysterectomy for FIGO Stage IB1 cervical cancer patients with tumor diameter preoperatively estimated 2 cm or less: Japan Clinical Oncology Group trial (JCOG1101); exploratory analysis before primary analysis.
Presenter: Takahide Arimoto
Session: Poster Display session 2
Resources:
Abstract
5352 - Impact of Combined Interstitial and Intracavitary Brachytherapy in locally advanced Cervical cancer: A Survival and toxicity profile assessment
Presenter: Vibhay Pareek
Session: Poster Display session 2
Resources:
Abstract
2049 - Chemoradiotherapy response prediction model by proteomic expressional profiling in patients with locally advanced cervical cancer
Presenter: Chel Hun Choi
Session: Poster Display session 2
Resources:
Abstract
1923 - Disparities starting adjuvant chemotherapy for locally advanced cervix cancer in the international, academic, randomised, phase 3 OUTBACK trial (ANZGOG 0902, RTOG 1174, NRG 0274)
Presenter: Linda Mileshkin
Session: Poster Display session 2
Resources:
Abstract
3284 - Primary results from CECILIA, a global single-arm phase 2 study evaluating bevacizumab (BEV), carboplatin (C) and paclitaxel (P) for advanced cervical cancer (aCC)
Presenter: Andres Redondo
Session: Poster Display session 2
Resources:
Abstract
843 - Prognostic and clinicopathological significance of PD-L1 in patients with cervical cancer: a meta-analysis
Presenter: Xiaobin Gu
Session: Poster Display session 2
Resources:
Abstract
1020 - Clinical impact of molecular profiling of cervical cancer (CC) patients (pts) in a dedicated Phase I (P1) unit
Presenter: Mariana Scaranti
Session: Poster Display session 2
Resources:
Abstract
872 - Comparative proteomic profiles of cervical cancer and paried paracancerous tissue and the potential effects of DUSP7 over-expression through inhibiting RAS pathway on the biological characteristics of human cervical cancer cell line SIHA
Presenter: Xuan Jiang
Session: Poster Display session 2
Resources:
Abstract
1988 - Molecular profiling reveals novel targetable biomarkers in neuroendocrine carcinoma of the uterine cervix
Presenter: Semir Vranic
Session: Poster Display session 2
Resources:
Abstract