Abstract 4066
Background
Breast cancer (BC) represents the most common malignancy and has the highest mortality among women, both in the world and in Kazakhstan. Approximately 20-30% of cases of hereditary breast cancer are caused by presence of BRCA1 and BRCA2 genes defects. Also, there are additional genes which can increase the risk of BC and they are still under study.The aim of this study was to identify new, detectable and objective markers of key cancer genes by next-generation sequencing (NGS) in BC patients.
Methods
The study included 194 unrelated patients (the av/age 34.25 ± 4.56) with BC. Genomic DNA was obtained from peripheral blood,next-generation sequencing was performed using TruSightCancer Kit on the MiSeq platform,studio Variant was used to annotate genetic variants.
Results
In total, 61 pathogenic variants (all in heterozygous state) were found in 56 (28.9%) patients,the vast majority of variants located in BRCA1 (n = 19/56; 33.9%), 15 in BRCA2 (26.8%). The frequency of pathogenic variants in genes TP53 (8.9%), PALB2 (5.4%), MSH6 (5.4%), CHEK2 (3.6%), SDHB (3.6%), and WRN (3.6%) were higher than those genes APC, ATM, FANCA, FANCM, MSH2, NBN, NF1, PMS1, PMS2, and XPA which include only one deleterious variants. The analysis of mutation type has revealed 28 frameshift mutations, 15 stop-gain mutations, 8 missense mutations, 8 splice site variants, 1 start lost variant, and 1 synonymous variant. In total, 43 mutations were unique, 15 of them represented novel variants. Those new mutations have not been previously mentioned in the LOVD and ClinVar databases and have not been described in publications. Population frequency of all detected pathogenic mutations in 1000G, ESP6500 and ExAC databases were less than 1%. 73.8% of the mutations were available in the dbSNP database. The most common pathogenic variants were c.5329dupC and c.5341-2delA (c.5278-2delA) in BRCA1 gene, accounting for 10.7% (n = 6/56) and 8.9% of patients (n = 5/56), respectively.
Conclusions
NGS showed frequent and novel germline mutations in BRCA1/2, CHEK2, TP53 and PALB2. After the final statistical data processing, diagnostic and prevention tools for key genes will be developed and included in the National guidelines for cancer diseases.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Kazakh Institute of Oncology and Radiology Institute of General Genetics and Cytology.
Funding
The Ministry of Healthcare of the Republic of Kazakhstan.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
1285 - Preliminary results of STELLAR-001, a dose escalation phase I study of the anti-C5aR, IPH5401, in combination with durvalumab in advanced solid tumors.
Presenter: Christophe Massard
Session: Poster Display session 3
Resources:
Abstract
3808 - GOLFIG chemo-immunotherapy in metastatic colorectal cancer (mCRC) patients: A fifteen year retrospective analysis
Presenter: Pierpaolo Correale
Session: Poster Display session 3
Resources:
Abstract
5677 - Immune correlates in peripheral blood samples in a preoperative window of opportunity randomized trial of nivolumab with or without tadalafil in resectable squamous cell carcinoma of the head and neck (SCCHN)
Presenter: Larry Harshyne
Session: Poster Display session 3
Resources:
Abstract
4854 - Phase 1 evaluation of AB928, a novel dual adenosine receptor antagonist, combined with chemotherapy or AB122 (anti-PD-1) in patients (pts) with advanced malignancies
Presenter: John Powderly
Session: Poster Display session 3
Resources:
Abstract
4344 - Phase 1 Trial of CV301 in Combination with Anti-PD-1 Therapy in Non-squamous NSCLC
Presenter: Arun Rajan
Session: Poster Display session 3
Resources:
Abstract
4555 - Safety and efficacy results of the combination of DPX-Survivac, pembrolizumab and intermittent low dose cyclophosphamide (CPA) in subjects with advanced and metastatic solid tumors: preliminary results from the hepatocellular carcinoma (HCC), NSCLC, bladder cancer, & MSI-H cohorts
Presenter: Henry Conter
Session: Poster Display session 3
Resources:
Abstract
3012 - Excellent CBR and Prolonged PFS in Non-Squamous NSCLC with Oral CA-170, an Inhibitor of VISTA and PD-L1
Presenter: Vivek Radhakrishnan
Session: Poster Display session 3
Resources:
Abstract
2536 - Phase Ib/II trial of TG4001 (Tipapkinogene sovacivec), a therapeutic HPV-vaccine, and Avelumab in patients with recurrent/metastatic (R/M) HPV-16+ cancers
Presenter: Christophe Le Tourneau
Session: Poster Display session 3
Resources:
Abstract
1845 - Induction of tumor-infiltrating functional CD8 positive cells and PD-L1 expression in esophageal cancer by S-588410
Presenter: Takashi Kojima
Session: Poster Display session 3
Resources:
Abstract
5043 - Comprehensive results of a Phase Ib study with a HER2/neu B-cell peptide vaccine administered with cisplatin and 5-fluorouracil or capecitabine chemotherapy show safety, immunogenicity and clinical response in patients with HER2/Neu overexpressing advanced gastric cancer
Presenter: Ursula Wiedermann
Session: Poster Display session 3
Resources:
Abstract