Profiling receptor tyrosine kinase fusions in Chinese breast cancers.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e15092-e15092
Author(s):  
Zhonghua Tao ◽  
Xichun Hu ◽  
Wen-Ming Cao ◽  
Jianxia Liu ◽  
Ting Li ◽  
...  

e15092 Background: Receptor tyrosine kinases (RTKs) are a class of tyrosine kinases that regulate cell-to-cell communication and control a variety of complex biological functions. Dysregulation of RTK signaling partly due to chromosomal rearrangements leads to novel tyrosine kinase fusion oncoproteins which are possibly driver alterations to cancers. Targeting some RTK fusions with specific tyrosine kinases inhibitors (TKIs) is an effective therapeutic strategy across a spectrum of RTK fusion-related cancers. However, there is still a paucity of extensive RTK fusion investigations in breast cancer. We aimed to characterize RTK fusions in Chinese breast cancer patients. Methods: An in-house sequencing database of 1440 Chinese breast cancer patients using a 520-gene NGS sequencing panel was thoroughly reviewed. RTK fusion was defined as an in-frame fusion with the tyrosine kinase domain of the RTK completely retained with the only exception of ERBB2 fusion which was not counted due to its unclear significance. Concomitant mutations and TMB were also analyzed and calculated. Patients’ clinical characteristics were retrieved from case records. Results: 27 RTK fusion-positive breast cancers (12 tissues + 15 plasmas) were identified, patients had a median age of 52 years. Triple-negative breast cancer subtype comprised 37% with luminal and HER2 positive subtypes being 40.8% and 22.2%, respectively. 77.8% of patients were at stage IV and 22.2% at stage I-III. Ten were treatment naïve. RTK fusions occurred in 2% of breast cancers in our database, compared with the prevalence of 0.6% and 1.3% in MSKCC and TCGA, respectively. In the subset of stage IV patients, our database showed a significantly higher RTK fusion frequency than that in MSKCC (3.2% vs. 0.6%, p = 0.013). FGFR2 fusions were seen most commonly (n = 7), followed by RET (n = 4), ROS1 (n = 3), NTRK3 (n = 3), BRAF (n = 2), and NTRK1 (n = 2). Other RTK fusions including ALK, EGFR, FGFR1, FGFR3, MET, and NTRK2 were identified in one patient each. Of note, the normalized abundance of RTK fusion (fusion AF/max AF) correlated negatively with TMB (r = -0.48, p = 0.017). Patients with TMB < 4 (Muts/Mb) displayed a higher fusion abundance than those with TMB ≥ 4 (Muts/Mb) (p = 0.018), suggesting a higher likelihood of subclonal nature for RTK fusions in TMB-high patients. Moreover, CREBBP mutation only co-occurred with FGFR2 fusion (p = 0.012), while NTRK3 fusion and TP53 mutation were mutually exclusive (p = 0.019). Conclusions: This is the first study comprehensively delineating the prevalence and spectrum of RTK fusions in Chinese breast cancers. Further study is ongoing to identify the enriched subpopulation which may benefit from RTK fusion inhibitors.

2021 ◽  
Vol 11 ◽  
Author(s):  
Zhonghua Tao ◽  
Jianxia Liu ◽  
Ting Li ◽  
Hong Xu ◽  
Kai Chen ◽  
...  

BackgroundReceptor tyrosine kinases (RTKs) are a class of tyrosine kinases that regulate cell-to-cell communication and control a variety of complex biological functions. Dysregulation of RTK signaling partly due to chromosomal rearrangements leads to novel tyrosine kinase fusion oncoproteins that are possibly driver alterations to cancers. Targeting some RTK fusions with specific tyrosine kinases inhibitors (TKIs) is an effective therapeutic strategy across a spectrum of RTK fusion-related cancers. However, there is still a paucity of extensive RTK fusion investigations in breast cancer. This study aims to characterize RTK fusions in Chinese breast cancer patients.MethodsAn in-house DNA sequencing database of 1440 Chinese breast cancer patients with a capture-based panel (520 gene or 108 gene-panel) was thoroughly reviewed. A total of 2,229 samples including 1,045 tissues and 1,184 plasmas were analyzed. RTK fusion was defined as an in-frame fusion with the tyrosine kinase domain of the RTK completely retained. Concomitant mutations were also analyzed and tumor mutational burden (TMB) was calculated. Patients’ clinical characteristics were retrieved from case records.ResultsA total of 30 RTK fusion events were identified from 27 breast cancer patients with a prevalence of 1.875%%. FGFR2 fusions were seen the most commonly (n=7), followed by RET (n=5), ROS1 (n=3), NTRK3 (n=3), BRAF (n=2), and NTRK1 (n=2). Other RTK fusions including ALK, EGFR, FGFR1, FGFR3, MET, and NTRK2 were identified in one patient each. A total of 27 unique resultant fusion proteins (22 with a novel partner) were discovered including 19 intrachromosomal rearrangements and 8 interchromosomal ones. Twenty-one fusions had the tyrosine kinase domain in-frame fused with a partner gene and six were juxtaposed with an intergenic space. Among the 27 fusions, FGFR2-WDR11 (E17: intergenic) (n=3) and ETV6-NTRK3 (E5:E15) (n=2) occurred recurrently. Of note, the normalized abundance of RTK fusion (fusion AF/max AF) correlated negatively with TMB (r=-0.48, P=0.017). Patients with TMB &lt; 8 (Mutations/Mb) displayed a higher fusion abundance than those with TMB ≥ 8 (Mutations/Mb) (P=0.025). Moreover, CREBBP mutation only co-occurred with FGFR2 fusion (P=0.012), while NTRK3 fusion and TP53 mutation were mutually exclusive (P=0.019).ConclusionThis is the first study comprehensively delineating the prevalence and spectrum of RTK fusions in Chinese breast cancers. Further study is ongoing to identify the enriched subpopulation who may benefit from RTK fusion inhibitors.


2020 ◽  
Vol 27 (8) ◽  
pp. 2711-2720 ◽  
Author(s):  
Ross Mudgway ◽  
Carlos Chavez de Paz Villanueva ◽  
Ann C. Lin ◽  
Maheswari Senthil ◽  
Carlos A. Garberoglio ◽  
...  

2021 ◽  
Vol 118 (29) ◽  
pp. e2026849118
Author(s):  
Rosalynd Upton ◽  
Allison Banuelos ◽  
Dongdong Feng ◽  
Tanuka Biswas ◽  
Kevin Kao ◽  
...  

Trastuzumab, a targeted anti-human epidermal-growth-factor receptor-2 (HER2) monoclonal antibody, represents a mainstay in the treatment of HER2-positive (HER2+) breast cancer. Although trastuzumab treatment is highly efficacious for early-stage HER2+ breast cancer, the majority of advanced-stage HER2+ breast cancer patients who initially respond to trastuzumab acquire resistance to treatment and relapse, despite persistence of HER2 gene amplification/overexpression. Here, we sought to leverage HER2 overexpression to engage antibody-dependent cellular phagocytosis (ADCP) through a combination of trastuzumab and anti-CD47 macrophage checkpoint immunotherapy. We have previously shown that blockade of CD47, a surface protein expressed by many malignancies (including HER2+ breast cancer), is an effective anticancer therapy. CD47 functions as a “don’t eat me” signal through its interaction with signal regulatory protein-α (SIRPα) on macrophages to inhibit phagocytosis. Hu5F9-G4 (magrolimab), a humanized monoclonal antibody against CD47, blocks CD47’s “don’t eat me” signal, thereby facilitating macrophage-mediated phagocytosis. Preclinical studies have shown that combining Hu5F9-G4 with tumor-targeting antibodies, such as rituximab, further enhances Hu5F9-G4’s anticancer effects via ADCP. Clinical trials have additionally demonstrated that Hu5F9-G4, in combination with rituximab, produced objective responses in patients whose diffuse large B cell lymphomas had developed resistance to rituximab and chemotherapy. These studies led us to hypothesize that combining Hu5F9-G4 with trastuzumab would produce an anticancer effect in antibody-dependent cellular cytotoxicity (ADCC)-tolerant HER2+ breast cancer. This combination significantly suppressed the growth of ADCC-tolerant HER2+ breast cancers via Fc-dependent ADCP. Our study demonstrates that combining trastuzumab and Hu5F9-G4 represents a potential new treatment option for HER2+ breast cancer patients, even for patients whose tumors have progressed after trastuzumab.


2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 152-152 ◽  
Author(s):  
Jerome Martin-Babau ◽  
Yves Eusen ◽  
Cedric Verveur ◽  
Fanny Trouboul ◽  
Caroline Cheneau ◽  
...  

152 Background: Trastuzumab is widely used in Her2 positive metastatic esophageal and gastric cancers along with chemotherapy. Cardiotoxicity of trastuzumab has been described precisely in Her2 positive breast cancers and occurs with asymptomatic lowering of LVEF (Left Ventricular Ejection Fraction) in up to 10% of cases. Esogastric cancer patients are usually older and have more comorbidities than patients followed for breast cancer. Methods: This monocentric retrospective study measured the incidence of symptomatic and asymptomatic cardiotoxicity in patients treated for metastatic esogastric cancers and its potential impact regarding overall survival from October 2009 to September 2015. Patients should receive trastuzumab with chemotherapy during the period of study for treatment of Her2 positive metastatic esogastric cancer as first-line chemotherapy. Results: 27 patients received trastuzumab along with chemotherapy during the period of study. Median age was 62.3 years, sex ratio 21 M/6 W. The median number of cycles of trastuzumab was 5 cycles. The asymptomatic cardiotoxicity rate, defined by a drop of more than 10% of LVEF between the enrollment echocardiogram and the third month treatment echocardiogram, was of 22%. Symptomatic cardiotoxicity was observed in two patients (7.4%), with one cardiac failure and one myocardial infarction, with no associated death. Cardiovascular comorbidities and cardiac irradiation which is recurrent in this indication did not appear as a predictive factor of cardiotoxicity (p = 1). Overall survival of patients was not statistically modified by the occurring of cardiotoxicity even if we noted a trend to better outcome of the patients presenting an asymptomatic LVEF lowering. Conclusions: This study is to our knowledge the first to focus specifically on the cardiotoxicity of trastuzumab in esogastric metastatic Her2 positive cancer in the real world. These patients seem to be at a higher asymptomatic cardiac risk than breast cancer patients. However cardiovascular comorbidities didn’t appear as predictive factors of trastuzumab induced cardiotoxicity and should not prevent patient from benefiting of this treatment.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 557-557 ◽  
Author(s):  
Florian Fitzal ◽  
Marija Balic ◽  
Vesna Bjelic-Radisic ◽  
Michael Hubalek ◽  
Christian F. Singer ◽  
...  

557 Background: The ABCSG 28 Posytive trial compared primary surgery versus primary systemic therapy without surgery in stage IV breast cancer patients. The primary aim was to investigate whether immediate resection of the primary tumor followed by standard systemic therapy improves median survival compared with no surgical resection (NCT01015625). The trial had to be stopped early due insufficient recruitment. Methods: Untreated stage IV breast cancer patients with the primary in situ were randomly assigned to either surgery of the primary versus no surgery followed by systemic therapy between 2011 and 2015 in 15 breast health centers in Austria. Systemic therapy included endocrine therapy or chemotherapy. Patients were routinely followed every 3-6 months. Primary endpoint was median survival. Results: 90 patients (45 with surgery, 45 with primary systemic therapy without surgery) were randomized. Stratification criteria were age, endocrine responsiveness, her2 expression, planned first line therapy and bone only versus other metastases. Patients in the surgery arm had more cT3 breast cancer (22% versus 7%) and more cN2 staging (16% versus 4%) as well as more her2 positive breast cancer cases (27% versus 18%). The median follow up was 37.5 months and immunohistochemical subtype analysis showed 9% basal like, 22% her2 positive, 51% luminal A and 13% luminal B cancers. Both groups were well balanced regarding first line treatment (endocrine versus chemotherapy) however, there were more taxane treated patients in the no surgery group (24.4 versus 15.6%). The median survival in the surgery arm was 34.6 months versus 54.8 months in the no surgery arm without statistical significance (HR 0.691 CI 0.358 – 1.333; p=0.267). Time to distant progression was insignificantly longer in the no surgery arm (surgery arm 13.9 versus no surgery arm 29.0 months). Conclusions: This first analysis of the prospective randomized phase III trial POSYTIVE-ABCSG-28 demonstrated no benefit in overall survival for immediate surgery of the primary in de novo stage IV breast cancer patients. Clinical trial information: NCT01015625.


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