Abstract 5578
Background
Testing for germline BRCA1/2 mutations has an established predictive role in breast and ovarian cancer risk assessment and EQA on germline mutation testing have been performed for a long time. With the European extension of indication for the PARP inhibitors, the screening of tumors first is increasingly important. However, tumoral BRCA1/2 testing is a different analytical process on formalin-fixed, paraffin-embedded (FFPE) material and with some challenging variants as large rearrangements. Validation of the test method and participation in external quality assessment programs are therefore required.
Methods
In the French national quality control programs (Gen&tiss) of 2017 and 2018, laboratories received 5 samples from ovarian cancer patients and 1 educational artificial sample with mutations present at different variant allelic frequencies in BRCA1/2 and a large rearrangement in BRCA1.
Results
The number of participants was 21 in 2017 and 26 in 2018. The number of labs with severe error was 3 in 2017 (14%) and 4 in 2018 (15%). For BRCA1, the average score remained stable between 2017 [9.6/10 (N = 21)] and 2018 [9.6/10 (N = 26)]. In both years, 2 laboratories made severe errors (false positive/false negative). In 2017 only 11 laboratories (N = 20) identified the educational variant present at 7% VAF. For BRCA2 the score slightly decreased from 9.8/10 (N = 22) to 9.4/10 (N = 26) and the number of laboratories with severe errors increased from 1 to 3. Half of the laboratories (N = 20) detected all three mutations present in the educational sample (VAF 10% to 30%) in the 2017 scheme. In 2018 a large deletion in BRCA1 present in the educational sample was only detected by 4 out of 20 laboratories. Three out of 26 laboratories detected the additional RAD51C variant and none the RAD51D variant. The main methods applied in France focus on BRCA1 and BRCA2 genes and amplification-based enrichment.
Conclusions
The genotype results were very similar between 2017 and 2018: acceptable but there are still more than 14% with severe errors. The limit of detection is a critical point. Few labs are ready to extend testing beyond BRCA1/2 genes. The question of large rearrangements is not yet solved for tumoral screening. EQA on tumoral BRCA1/2 testing is therefore essential to improve laboratory performance.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Gen&tiss - GFCO and AFAQAP.
Funding
AstraZeneca.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
1945 - Randomized Phase II Study of Trabectedin/Olaparib Compared to Physician’s Choice in Subjects with Previously Treated Advanced or Recurrent Solid Tumors Harboring DNA Repair Deficiencies.
Presenter: Christoph Heilig
Session: Poster Display session 3
Resources:
Abstract
3021 - Homogenisation of Leftover Surgical Tissue across multiple cancer types: a Feasibility Study (HoLST-F)
Presenter: Lavinia Spain
Session: Poster Display session 3
Resources:
Abstract
2882 - Safety, efficacy, and immune effects of intratumoral tilsotolimod in patients with refractory solid tumors: updated results from ILLUMINATE-101
Presenter: Hani Babiker
Session: Poster Display session 3
Resources:
Abstract
1950 - Phase 1 Dose Escalation of MSC-1, a humanized anti-LIF monoclonal antibody, in patients (pts) with advanced solid tumors: Updated results
Presenter: Erkut Borazanci
Session: Poster Display session 3
Resources:
Abstract
2391 - A phase 1 study of Sym021, an anti-PD-1 antibody (Ab), alone and in combination with Sym022 (anti-LAG-3) or Sym023 (anti-TIM-3)
Presenter: Anna Spreafico
Session: Poster Display session 3
Resources:
Abstract
5692 - FPA150 (B7-H4 antibody) Phase 1 Update in Advanced Solid Tumors: Monotherapy and in Combination with Pembrolizumab
Presenter: Zev Wainberg
Session: Poster Display session 3
Resources:
Abstract
2416 - MG1124, a novel CEACAM1-targeted monoclonal antibody, has therapeutic potential as a combination partner of PD-1 inhibitors in NSCLC patients
Presenter: Eun Hee Lee
Session: Poster Display session 3
Resources:
Abstract
2661 - Tumor stroma targeting and modulation by OMTX705 ADC, a novel and potent immunotherapeutic treatment of solid tumors.
Presenter: Myriam Fabre
Session: Poster Display session 3
Resources:
Abstract
3681 - Durvalumab + monalizumab, mFOLFOX6, and bevacizumab in patients (pts) with metastatic microsatellite-stable colorectal cancer (MSS-CRC)
Presenter: May Cho
Session: Poster Display session 3
Resources:
Abstract
2664 - Phase (Ph) II study of MBG453 + spartalizumab in patients (pts) with non-small cell lung cancer (NSCLC) and melanoma pretreated with anti–PD-1/L1 therapy
Presenter: Nicholas Mach
Session: Poster Display session 3
Resources:
Abstract