Detection of actionable gene mutations in breast cancer by amplicon-based next-generation sequencing liquid biopsy.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 1035-1035
Author(s):  
Jing Shan Lim ◽  
Yukti Choudhury ◽  
Wai Min Phyo ◽  
Chaitanya Gupta ◽  
Yiliang Ho ◽  
...  

1035 Background: The PI3K-inhibitor, alpelisib, was approved for the treatment of hormone receptor (HR)-positive, HER2-negative breast cancers with PIK3CA mutations based on findings from the SOLAR-1 trial. PIK3CA-positivity in tumor tissue was 29% (341/1172), but was only 15% (177/1172) in plasma cell-free DNA (cfDNA). The lower mutation detection rate observed in cfDNA may limit the clinical application of liquid biopsy in breast cancer. Amplicon-based next-generation sequencing (NGS) approach may confer improved sensitivity, allowing more effective profiling. We conducted a study to evaluate the use of this technology. Methods: Plasma cfDNA from 113 breast cancer patients (82.3% metastatic) underwent real-world testing in a CAP and ISO15189 accredited central laboratory. We analysed genetic alterations in cfDNA using an amplicon-based NGS technology. The presence of PIK3CA and other mutations relevant to breast cancer were correlated to molecular subtypes and treatment histories. Results: At least one mutation was detected in 70.8% of cases. Mutations were more frequent in metastatic cases (77.4%) compared to non-metastatic cases (27.3%). Across all patients, mutations in PIK3CA (33.6%), TP53 (32.7%), ESR1 (22.1%), GATA3 (7.1%) and ERBB2 (7.1%) were most frequently detected, in accordance with tumor tissue genotyping studies. PIK3CA mutations were more common in HR+ HER2- patients (44.4% vs 28.6% of other patients). Among PIK3CA-mutant cases, multiple PIK3CA mutations were present in 18.4% of cases, and hotspot mutations H1047R (34.2%), E542K (26.3%) and E545K (15.8%) were most frequent. An association was seen between PIK3CA mutation and prior treatment with CDK4/6 inhibitors (palbociclib, ribociclib) or mTOR inhibitor (everolimus), with 58% of PIK3CA-mutant cases having received these treatment previously compared to only 20% of PIK3CA-wild type (wt) cases. In addition, 75% of previously treated ESR1-mutant cases had specifically received hormonal treatment, compared to 60 % of ESR1-wt cases that received any treatment. Conclusions: We report similar PIK3CA mutation frequencies (~30%) with amplicon-based NGS on cfDNA compared to tumor tissue testing in breast cancer. Importantly, other driver mutations were also observed at similar frequencies as external tissue studies, implying high sensitivity as the primary reason for performance. This supports the clinical utility of an amplicon-based NGS-based approach to liquid biopsy for the sensitive detection of actionable mutations in breast cancer.

2020 ◽  
Vol 15 ◽  
Author(s):  
Zheng Jiang ◽  
Hui Liu ◽  
Siwen Zhang ◽  
Jia Liu ◽  
Weitao Wang ◽  
...  

Background: Microsatellite instability (MSI) is a prognostic biomarker used to guide medication selection in multiple cancers, such as colorectal cancer. Traditional PCR with capillary electrophoresis and next-generation sequencing using paired tumor tissue and leukocyte samples are the main approaches for MSI detection due to their high sensitivity and specificity. Currently, patient tissue samples are obtained through puncture or surgery, which causes injury and risk of concurrent disease, further illustrating the need for MSI detection by liquid biopsy. Methods: We propose an analytic method using paired plasma/leukocyte samples and MSI detection using next-generation sequencing technology. Based on the theoretical progress of oncogenesis, we hypothesized that the microsatellite site length in plasma equals the combination of the distribution of tumor tissue and leukocytes. Thus, we defined a window-judgement method to identify whether biomarkers were stable. Results: Compared to traditional PCR as the standard, we evaluated three methods in 20 samples (MSI-H:3/MSS:17): peak shifting method using tissue vs. leukocytes, peak shifting method using plasma vs. leukocytes, and our method using plasma vs. leukocytes. Compared to traditional PCR, we observed a sensitivity of 100%, 0%, and 100%, and a specificity of 100.00%, 94.12%, and 88.24%, respectively. Conclusion: Our method has the advantage of possibly detecting MSI in a liquid biopsy and provides a novel direction for future studies to increase the specificity of the method.


2019 ◽  
pp. 1-26
Author(s):  
Frankie Ann Holmes ◽  
Maren K. Levin ◽  
Ying Cao ◽  
Sohail Balasubramanian ◽  
Jeffrey S. Ross ◽  
...  

PURPOSE To identify proteomic and genomic alterations in residual disease (RD) for human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer (BC) after preoperative trastuzumab (H), lapatinib (L), or both (H+L) in combination with chemotherapy. PATIENTS AND METHODS Patients with stage II/III HER2+ BC (n = 100) were randomly assigned to preoperative treatment with H versus L 1,250mg versus H+L (L: 750 to 1,000 mg) plus 5-fluorouracil, epirubicin, and cyclophosphamide, followed by weekly paclitaxel. After receiving institutional review board–approved informed consent, targeted next-generation sequencing was performed on 20 patients’ formalin-fixed paraffin embedded tumors to characterize genomic alterations across 287 cancer-related genes. Reverse phase protein array (RPPA) analysis was performed on both the baseline biopsy and RD specimens, when available. RESULTS Two of 20 RD tissues were HER2 negative per next-generation sequencing; one sample had insufficient tissue. Of six pretreatment biopsy specimens, four were comutated with TP53 and PIK3CA. Of 17 HER2+ RD, seven specimens (41%) had PIK3CA mutations always comutated with TP53, and four (24%) also had concurrent CDK12 amplification. Overall, CDK12 amplification was observed in eight of the 17 (47%) HER2+ RD specimens. A total of 12 RD specimens (71%) had TP53 mutations. Although prevalence of individual TP53 and PIK3CA mutations was only modestly higher than published estimates for those in HER2+ primary BCs (55% and 32% for TP53 and PIK3CA, respectively), prevalence of these as comutations appeared higher (41%), compared with less than 10% in several series. On RPPA analysis of the RD tissue with comutations, the strongest Spearman ρ correlations were limited to EGFR and phospho-AKT (ρ, 0.999; P = .019) and phospho-mTOR and phospho-S6 ribosomal protein (ρ, 0.994; P = .048). CONCLUSION HER2-amplified RD tissue after preoperative H, L, or H+L plus chemotherapy was enriched for PIK3CA and TP53 comutations, and the RD tissue demonstrated activation of EGFR/AKT/mTOR signaling on RPPA.


2017 ◽  
Vol 16 (7) ◽  
pp. 1412-1420 ◽  
Author(s):  
Young Kwang Chae ◽  
Andrew A. Davis ◽  
Sarika Jain ◽  
Cesar Santa-Maria ◽  
Lisa Flaum ◽  
...  

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4564
Author(s):  
Simona Bruzas ◽  
Sherko Kuemmel ◽  
Hakima Harrach ◽  
Elisabeth Breit ◽  
Beyhan Ataseven ◽  
...  

Next-generation sequencing (NGS) followed by matched therapy has opened up new therapeutic options to patients with metastatic breast cancer (mBC). Here we report our experience with this approach in everyday clinical practice. This retrospective study included 95 patients with mBC who were genotyped with the FoundationOne® (CDx) assay in a commercial molecular pathology laboratory. Genetic alterations were identified in all tumor specimens, and 83 patients (87.4%) had a median of 2 (range, 1–6) potentially actionable alterations. A multidisciplinary tumor board recommended genomically guided therapy to 63 patients, 30 of whom received such treatment. Everolimus (n = 15) and anti-human epidermal growth factor receptor 2 (HER2) therapy (n = 6) were most frequently administered. The ratio of progression-free survival (PFS) under NGS-based therapy to PFS under the last line of standard therapy prior to NGS was >1.3 in 13 (43.3%) patients, indicative of a clinical benefit to NGS-directed therapy. One-year overall survival rates were 22.7% (95% CI, 6.5–44.4) in 65 patients allocated to the standard therapy versus 62.9% (95% CI, 41.6–78.2) in 30 patients receiving the matched therapy. In conclusion, NGS-matched treatment improved the clinical outcomes in a subgroup of mBC patients.


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