Extracellular Domain Levels Research Articles

Abstract 7634: HER2 extracellular domain in serum samples from HER2+ metastatic breast cancer patients as a potential biomarker of progression-free survival

Abstract Introduction: The detection of serum biomarkers holds potential for non-invasive methods for early cancer detection, monitoring of disease progression, and assessment of treatment responses leading to earlier interventions that may significantly improve patient outcomes. Human epidermal growth factor receptor 2 (HER2) overexpression plays a key role in the prognosis of HER2+ breast cancer (BC). While HER2 is well-established as a cell surface marker, its soluble extracellular domain (ECD) in serum has gained attention as a potential prognostic biomarker. Elevated levels of HER2 ECD (>15ng/ml) have been associated with a poor outcome. However only a small percentage of primary BC patients have levels of HER2 ECD >15ng/ml. Research has suggested that HER2 targeted therapies can influence the rate of HER2 ECD shedding. Therefore, this study aimed to explore the association between circulating HER2 ECD levels with progression-free survival (PFS) and overall survival (OS) in patients with metastatic HER2+ BC. Methods: Matched Pre and post treatment serum samples (n=25) from BC patients enrolled in TH V THL (ICORG (CTRIAL-IE) 11-10/NCT01526369) clinical trial were assessed. Human ErbB2 (HER2) ELISA Kit (Invitrogen) was used to detect levels of soluble HER2 ECD in the serum. Serum levels were stratified as Low (<300pg/ml n=5), Intermediate (300-700pg/ml n=10) or High (>700pg/ml n=10). Patient data correlation was used to assess PFS and OS, Kaplan-Meier survival curves were constructed based on the serum levels of HER2 ECD. Significance p values were determined using log-rank (Mantel-Cox) test. Results: Levels of HER2 ECD detected (94-1730pg/ml) did not exceed 15ng/ml for any sample. There was no significant difference in HER2 ECD levels between treatment arms (TH vs. THL) for PFS (p=0.4685) or OS (p=0.1376). There was no change between the pre and post treatment HER2 ECD serum levels in the samples tested (p=0.344). However, when pre-treatment samples were stratified based on Low, Intermediate or High HER2 ECD levels, there was a significant increase in PFS for patients in the High cohort. Median PFS increased from 8.31 months in the Low cohort to 13.57 months in the Intermediate cohort. The median PFS increased further to 22.24 months in the High cohort (Log rank p=0.0197). The same parameters were applied for the analysis of OS, which also improved as the level of HER2 ECD increased. Median OS increased from 35.19 months (Low) to 68.7 months (Intermediate), with a Median OS not reached for the High cohort (Log rank p=0.077). Conclusions: Patients with HER2 ECD levels above 700pg/ml display a survival advantage in this limited study. Further validation and prospective studies are warranted to fully establish the clinical utility of HER2 ECD as a biomarker in metastatic HER2+ BC. Citation Format: Debbie O'Reilly, Marc Nolan, Ausra Teiserskiene, Bryan T. Hennessy, John Crown, Denis M. Collins. HER2 extracellular domain in serum samples from HER2+ metastatic breast cancer patients as a potential biomarker of progression-free survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7634.

Soluble p75 neurotrophic receptor as a reliable biomarker in neurodegenerative diseases: what is the evidence?

Neurodegenerative diseases are often misdiagnosed, especially when the diagnosis is based solely on clinical symptoms. The p75 neurotrophic receptor (p75NTR) has been studied as an index of sensory and motor nerve development and maturation. Its cleavable extracellular domain (ECD) is readily detectable in various biological fluids including plasma, serum and urine. There is evidence for increased p75NTR ECD levels in neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis, age-related dementia, schizophrenia, and diabetic neuropathy. Whether p75NTR ECD could be used as a biomarker for diagnosis and/or prognosis in these disorders, and whether it could potentially lead to the development of targeted therapies, remains an open question. In this review, we present and discuss published studies that have evaluated the relevance of this emerging biomarker in the context of various neurodegenerative diseases. We also highlight areas that require further investigation to better understand the role of p75NTR ECD in the clinical diagnosis and management of neurodegenerative disorders.

Active immunotherapy reduces NOTCH3 deposition in brain capillaries in a CADASIL mouse model

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of familial small vessel disease; no preventive or curative therapy is available. CADASIL is caused by mutations in the NOTCH3 gene, resulting in a mutated NOTCH3 receptor, with aggregation of the NOTCH3 extracellular domain (ECD) around vascular smooth muscle cells. In this study, we have developed a novel active immunization therapy specifically targeting CADASIL‐like aggregated NOTCH3 ECD. Immunizing CADASIL TgN3R182C150 mice with aggregates composed of CADASIL‐R133C mutated and wild‐type EGF1–5 repeats for a total of 4 months resulted in a marked reduction (38–48%) in NOTCH3 deposition around brain capillaries, increased microglia activation and lowered serum levels of NOTCH3 ECD. Active immunization did not impact body weight, general behavior, the number and integrity of vascular smooth muscle cells in the retina, neuronal survival, or inflammation or the renal system, suggesting that the therapy is tolerable. This is the first therapeutic study reporting a successful reduction of NOTCH3 accumulation in a CADASIL mouse model supporting further development towards clinical application for the benefit of CADASIL patients.

Prognostic Value of the Serum HER2 Extracellular Domain Level in Breast Cancer: A Systematic Review and Meta-Analysis.

Simple SummaryWe performed a systematic review and meta-analysis evaluating the predictive value of the serum HER2 extracellular domain (sHER2 ECD) for breast cancer prognosis. Our review investigated 40 studies (12,229 patients) that assessed the impact of the sHER2 ECD levels on breast cancer prognosis and explored the clinical significance of sHER2 ECD levels in different treatment modalities. Our findings indicated that an elevated sHER2 was an unfavorable prognostic factor in breast cancer. More interestingly, sHER2 ECD was found to be a promising biomarker for predicting adverse clinical outcomes of trastuzumab-based treatment but did not affect the efficacy of tyrosine kinase inhibitors. In addition, the baseline cutoff value of sHER2 ECD in different treatment stages of breast cancer remains to be further explored. Overall, our study suggested that sHER2 ECD levels have important prognostic value in breast cancer and may be helpful for clinicians to select the appropriate anti-HER2 therapy for HER2-positive breast cancer, providing more evidence for guiding clinical practice.An elevated serum HER2 extracellular domain is associated with poor prognosis in breast cancer, but the relationship between sHER2 and the efficacy of different modalities remains controversial. Herein, we aimed to evaluate the prognostic value of serum HER2 extracellular domain (sHER2 ECD) in breast cancer and to identify its correlation with the efficacy of different treatment regimens. A systematic search of the PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases was conducted to identify studies exploring the association between HER2 ECD level and clinical outcomes among patients with breast cancer. Using the random effects models, pooled hazard ratios (HRs), and odds ratios (ORs) with 95% confidence intervals (CI), were calculated for progression-free survival (PFS), overall survival (OS), disease-free survival (DFS), and the objective response rate (ORR). Heterogeneity was further evaluated by subgroup and sensitivity analysis. Overall, 40 studies comprising 12,229 patients were included in this systematic review and meta-analysis. Elevated HER2 ECD levels were associated with worse PFS (HR 1.74, 95% CI 1.40–2.17; p < 0.001), and this effect was observed in patients treated with chemotherapy (HR 1.81, 95% CI 1.37–2.39; p < 0.001), endocrine therapy (HR 1.91, 95% CI 1.57–2.32; p < 0.001), and trastuzumab (HR 1.74, 95% CI 1.31–2.30; p < 0.001). However, this association was not present in patients treated with tyrosine kinase inhibitors (TKIs) (HR 1.44, 95% CI 0.85–2.43, p = 0.17). The HRs/ORs for an elevated HER2 ECD level for DFS, OS, and ORR were 2.73 (95% CI 2.17–3.42; p < 0.001), 2.13 (95% CI 1.77–2.57; p < 0.001), and 0.80 (95% CI 0.49–1.31; p = 0.381), respectively. An elevated sHER2 ECD was an unfavorable prognostic factor in breast cancer but did not affect the efficacy of tyrosine kinase inhibitors such as lapatinib. Detection of sHER2 ECD may be helpful for clinicians selecting the appropriate anti-HER2 therapy for patients with HER2-positive breast cancer.

Clinical Correlates Identify ProBDNF and Thrombo-Inflammatory Markers as Key Predictors of Circulating p75NTR Extracellular Domain Levels in Older Adults.

The p75NTR receptor binds all neurotrophins and is mostly known for its role in neuronal survival and apoptosis. Recently, the extracellular domain (ECD) of p75NTR has been reported in plasma, its levels being dysregulated in numerous neurological diseases. However, the factors associated with p75NTR ECD levels remain unknown. We investigated clinical correlates of plasma p75NTR ECD levels in older adults without clinically manifested neurological disorders. Circulating p75NTR levels were measured by enzyme-linked immunosorbent assay in plasma obtained from participants in the BEL-AGE cohort (n = 1,280). Determinants of plasma p75NTR ECD levels were explored using linear and non-linear statistical models. Plasma p75NTR ECD levels were higher in male participants; were positively correlated with circulating concentrations of pro-brain-derived neurotrophic factor, and inflammatory markers interleukin-6 and CD40 Ligand; and were negatively correlated with the platelet activation marker P-selectin. While most individuals had p75NTR levels ranging from 43 to 358 pg/ml, high p75NTR levels reaching up to 9,000 pg/ml were detectable in a subgroup representing 15% of the individuals studied. In this cohort of older adults without clinically manifested neurological disorders, there was no association between plasma p75NTR ECD levels and cognitive performance, as assessed by the Montreal Cognitive Assessment score. The physiological relevance of high p75NTR ECD levels in plasma warrants further investigation. Further research assessing the source of circulating p75NTR is needed for a deeper understanding of the direction of effect, and to investigate whether high p75NTR ECD levels are predictive biomarkers or consequences of neuropathology.

Shed HER2 surrogacy evaluation in primary breast cancer patients: a study assessing tumor tissue HER2 expression at both extracellular and intracellular levels

The aim of the present study was to investigate serum HER2 extracellular domain (ECD) as a putative surrogate marker of the shedding phenomenon of HER2 receptor from the tumor tissue of primary breast cancer (BC) patients. A pilot retrospective study was conducted on 100 matched serum and tissue samples from patients with node-positive primary BC, stage II/III. Analysis of association and concordance between serum HER2 ECD levels (measured by chemiluminescence immunoassay) and the expression in matched tumor tissue of HER2 ECD and intracellular receptor domain (ICD) (determined by immunohistochemistry) were performed. The median serum HER2 ECD level was 9.4 ng/ml and cutoff values were set at 15.2 ng/ml or 13.0 ng/ml. HER2 ICD and ECD were overexpressed in tumor tissue of 19.8% and 6.9% of patients, respectively. Statistically significant associations were found between serum HER2 ECD levels and tissue expression of both HER2 ICD and ECD (p < .001; Fisher analysis). Moreover, strong concordances were found between serum HER2 ECD levels and tissue expression of HER2 ICD or ECD (cutoff 15.2 ng/ml: 80 and 92.5%, respectively). Our findings support a role for serum HER2 ECD as a surrogate marker of tissue HER2 status in primary BC, both for HER2 ICD or ECD expression.

Investigating the Levels of Shed Extracellular Domain of HER2 Protein in the Sera of Bladder Cancer Patients

Background: Receptor tyrosine-protein kinase ERBB2, also known as human epidermal growth factor receptor-2 (HER2), is heterogeneously expressed in a variety of human cancers, including bladder cancer. Based on previous studies that show its association with bladder cancer progression, HER2 has been included in novel multiplatform biomarkers for prediction of bladder cancer prognosis. However, the clinical significance of HER2 status remains underinvestigated and poorly linked to the patients’ clinicopathological features. Here, we aim to scrutinize the levels of the extracellular domain of HER2 in the sera of bladder cancer patients and correlate these levels with clinicopathological features of the tumor.Methods: In the present analytical cross-sectional study, we enrolled 60 pathologically confirmed bladder cancer patients along with 20 age-sex matched healthy controls, and compared their serum HER2 levels as measured by enzyme-linked immunosorbent assay.Results:We observed no statistically significant difference when comparing the levels of HER2 in the sera of cases and controls (P>0.05). Interestingly, serum HER2 levels of controls were higher than bladder cancer patients who had lymph node metastasis (P=0.036). Serum levels of HER2 were also higher in controls than bladder cancer patients with perineural invasion (P=0.028). We observed significantly higher HER2 serum levels in transitional cell carcinoma patients in comparison to non-transitional cell carcinoma patients (P=0.016).Conclusion: Our observations are suggestive of the absence of any association between bladder cancer prognostic factors and serum HER2 levels. To draw any definitive conclusion, further studies with larger sample sizes that examine the presence of neutralizing auto-antibodies against serum HER2, immunohistochemistry examination of HER2 in bladder tumor and lymph node samples, and urinary HER2 levels, along with measurement of its serum levels would be helpful.

Prognostic value of baseline serum HER2 extracellular domain level with a cut-off value of 15ng/mL in patients with breast cancer: a systematic review and meta-analysis.

The extracellular domain (ECD) of human epidermal growth factor receptor-2 (HER2) in the blood is a promising biomarker of cancer prognosis and response to therapy, whereas the clinical prognostic role of serum HER2 ECD (sHER2 ECD) level in patients with BC remains controversial. Moreover, its cut-off value significantly varies. Thus, this meta-analysis aimed to quantify the prognostic impact of this biomarker with a specific cut-off value in patients with BC. A systematic review of electronic databases was conducted to identify studies that assessed the association between baseline sHER2 ECD level with a cut-off value of 15ng/mL and clinical outcomes in patients with BC. Overall survival (OS) was the primary endpoint, and disease-free survival (DFS), progression-free survival (PFS), and time to progression (TTP) were the secondary endpoints. An inverse variance random effects meta-analysis was conducted. Twenty-three studies that included 8231patients with BC who met the inclusion criteria were included. An elevated baseline sHER2 ECD level was associated with a hazard ratio (HR) of 2.28 (95% confidence interval [CI] 2.00-2.61; P < 0.001) for OS, and this effect was observed in all subgroups. The HRs for an elevated sHER2 ECD level for DFS, PFS, and TTP were 2.52 (95% CI 1.90-3.35; P < 0.001), 1.63 (95% CI 1.37-1.95; P < 0.001), and 1.98 (95% CI 1.66-2.36; P < 0.001), respectively. An elevated sHER2 ECD level with a cut-off value of 15ng/mL was associated with poor clinical prognosis in patients with BC. Future studies should be conducted to reduce confounding and explore the mechanism.

Abstract P2-09-07: Low levels of HER2 extracellular domain (ECD) compared to intracelluar domain (ICD) in NeoALTTO may segregate benefit from lapatinib and trastuzumab in breast cancer

Abstract Background: Preclinical models suggest that in some HER2 overexpressed breast cancer cases, the extracellular domain of HER2, containing the binding region for trastuzumab (T) is not present due to proteolytic cleavage. Previous measurement of HER2 ECD and ICD in HeCOG 10/05 suggested that breast cancer cases that have low levels of ECD show decreased benefit from adjuvant T therapy (Carvajal et al, 2015). These cases may be more likely to show benefit from lapatinib(L), a small molecular tyrosine kinase inhibitor. NeoALTTO, an international multi-institutional trial comparing pre-surgical treatment with L vs T vs both, showed that pCR rates were around 25-30% for L or T but increased to 50% for both. This cohort allows us to test the hypothesis that patients with low ECD may benefit more from L than T. Methods: ECD and ICD were measured 382 cases using quantitative immunofluorescence (QIF) with domain specific antibodies (SP3, Spring biosciences for ECD and CB11, Biocare for ICD). Slides were stained and scanned, then measured using the AQUA method of QIF. All fields of view were scored and FOVs were averaged to generate a QIF score for each case. Index TMAs were used to standardize all autostainer runs and to define the QIF score cut-point that is equivalent to the clinical cut-point for the index TMA cases. Each case was then assigned to one of three groups; 1) High ECD and ICD, 2) Low ECD but High ICD, and 3) low ICD. Results: In the lapatinib arm, both group 1 and 2 showed a pCR rate of 25% (p&amp;gt;0.99), but in the trastuzumab arm, Group 1 pCR rate was 34% compared to 19% for group 2 (p=0.38). In the combination arm, group 1 showed a pCR rate of 59% compared to 29% for group 2 (p=0.046). In a logistic regression model for pCR, after adjustment for treatment arm and HR status the ECD/ICD status shows a significant predictive value (p = 0.002). Although this study is not powered for event free survival (EFS), at 6 years of follow up we found that patients in group 2 on the lapatinib arm show 92% EFS compared to 69% EFS in group 1 (p=0.17). The opposite trend is seen in both trastuzumab arms where EFS for group 1 on T showed 70% vs 62% for group 2 (p=0.57) and 77% vs 71% on the T+L arm (p=0.74). In a Cox regression model for EFS after adjustment for treatment arm and HR status, the ECD/ICD status is not significant (p=0.88) Conclusions: Cases with low levels of ECD compared to ICD appear benefit less than those with high levels of both ECD and ICD as assessed by pCR from treatments containing T. In contrast, those same patients also appear to benefit more, as assessed by EFS, on the L arm. These observations are consistent with the hypothesis that this assay could stratify benefit from L vs T based on the status of the ECD. Further assessment using this assay on the ALTTO cases is currently underway and may help confirm this observation. Citation Format: Rimm DL, Carvajal-Hausdorf D, Harbeck N, Fumagalli D, Rodrik-Outmezguine V, delaPena L, deAzambuja E, Huober J, Baselga J, Piccart M, Holmes E, Pusztai L. Low levels of HER2 extracellular domain (ECD) compared to intracelluar domain (ICD) in NeoALTTO may segregate benefit from lapatinib and trastuzumab in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-07.

Objective, domain-specific HER2 measurement in uterine and ovarian serous carcinomas and its clinical significance

IntroductionHER2 overexpression/amplification is identified in up to 40% of uterine serous carcinomas (USC) and 10% of ovarian serous carcinomas (OSC). However, clinical trials using various HER2-targeted agents failed to show significant responses. FDA-approved HER2 assays target only the protein's intracellular domain (ICD) and not the extracellular domain (ECD). Previous quantitative studies in breast cancer by our group have shown that ICD of HER2 is expressed in some cases that do not express the HER2 ECD. We measured HER2 ICD and ECD in USC and OSC samples, and determined their relationship with clinico-pathologic characteristics and survival. MethodsWe measured HER2 ICD and ECD levels in 2 cohorts of USC and OSC comprising 102 and 175 patients, respectively. HER2 antibodies targeting ICD (CB11) and ECD (SP3) were validated and standardized using the AQUA® method of quantitative immunofluorescence (QIF) and a previously reported HER2 standardization tissue microarray (TMA). Objective, population-based cut-points were used to stratify patients according to HER2 ICD/ECD status. ResultsIn USC, 8% of patients with high HER2 ICD had low ECD levels (6/75 patients). In OSC, 42% of patients with high HER2 ICD had low ECD levels (29/69 patients). HER2 ICD/ECD status in USC and OSC was not significantly associated with major clinico-pathological features or survival. ConclusionUsing objective, domain-specific HER2 measurement, 8% of USC and 42% of OSC patients with high HER2 ICD levels do not show uniform overexpression of the ECD. This may be related to the presence of p95 HER2, an oncogenic fragment generated by full protein cleavage or alternative initiation of translation. These observations raise the possibility that USC/OSCs expressing low ECD despite being HER2-positive by ICD measurement, may benefit from therapies directed against the intracellular domain (e.g. lapatinib or afatinib) alone or in combination with extracellular domain-directed drugs (e.g. trastuzumab, pertuzumab, T-DM1).

Biomarker analysis of the NeoSphere study: pertuzumab, trastuzumab, and docetaxel versus trastuzumab plus docetaxel, pertuzumab plus trastuzumab, or pertuzumab plus docetaxel for the neoadjuvant treatment of HER2-positive breast cancer

BackgroundNeoSphere showed significantly higher pathologic complete response (pCR) with neoadjuvant pertuzumab, trastuzumab, and docetaxel compared with trastuzumab plus docetaxel, pertuzumab plus trastuzumab, or pertuzumab plus docetaxel. We assessed associations between human epidermal growth factor receptor 2 (HER2) pathway-related biomarkers and clinical outcome in response to these regimens.MethodsTumor, serum, and whole blood samples were collected at baseline and post neoadjuvant treatment before surgery. Associations between biomarkers and pCR, and between biomarkers and clinical variables were assessed in the overall and estrogen receptor (ER)-positive and ER-negative populations. Changes in serum marker levels between baseline and post-neoadjuvant treatment were examined.ResultsNo markers were associated with pCR across all groups; however, significant associations were observed for two markers in individual groups. High HER2 was significantly associated with higher pCR rates (P = 0.001) and a significant treatment interaction (P = 0.0236) with pertuzumab, trastuzumab, and docetaxel (odds ratio 2.07, P = 0.01). Low serum transforming growth factor alpha (TGFα) was associated with higher pCR rates with pertuzumab plus trastuzumab (P = 0.04) without a significant treatment interaction. Presence of truncated HER2 did not affect pCR. A non-significant decreased pCR benefit was observed consistently across groups in patients with mutated PIK3CA while the treatment benefit from pertuzumab was maintained when comparing the trastuzumab plus docetaxel and pertuzumab, trastuzumab, and docetaxel groups. Notably, PIK3CA exon 9 mutations were associated with residual disease (pooled groups), which was not found for exon 20 mutations. Serum HER2 extracellular domain levels were significantly increased between baseline and post-neoadjuvant treatment in the non-trastuzumab-treated group, and decreased in the trastuzumab-containing groups (likely due to trastuzumab’s mechanism of action). Differences in biomarker profiles according to ER status were observed.ConclusionsThe observed associations of HER2 protein levels with sensitivity to pertuzumab, and of PIK3CA exon 9 mutation to lack of sensitivity to HER2-targeted monoclonal antibody treatment, warrant further investigation. Previously reported findings of truncated forms of HER2 as resistance markers to HER2-targeted treatment could not be confirmed in NeoSphere. Conventional HER2 assessment should continue and HER2 remains the only biomarker suitable for patient selection in this population.Trial registrationClinicaltrials.gov, NCT00545688. Registered on 16 October 2007.

Serum HER2 as a predictive biomarker for tissue HER2 status and prognosis in patients with gastric cancer.

AIMTo investigate the association between serum human epidermal growth factor receptor 2 (HER2) extracellular domain (ECD) and tissue HER2 status, and the prognostic value of serum HER2 ECD in patients with gastric cancer.METHODSA total of 239 patients with gastric cancer were enrolled from December 2012 to June 2013. Serum HER2 ECD was determined by chemiluminescent assay, and tissue HER2 status was evaluated by immunohistochemistry and fluorescence in situ hybridization assay. A receiver operating characteristic (ROC) curve was plotted to identify the optimal cut-off value for serum HER2 ECD assay for predicting survival in gastric cancer patients.RESULTSSerum HER2 ECD was significantly correlated with tissue HER2 status (P < 0.001), tumor size (P < 0.001), and intestinal type of gastric cancer (P = 0.021). Serum HER2 ECD levels differed significantly between patients with HER2-positive tissue expression and those with HER2-negative tissue expression. ROC analysis yielded an area under the curve value of 0.79 (95%CI: 0.71-0.87, P < 0.001), with a sensitivity and specificity of 0.54 (95%CI: 0.37-0.70) and 0.93 (95%CI: 0.88-0.96), respectively. With a cut-off value of 24.75 ng/mL, high serum HER2 ECD had a negative impact on overall survival of the patients (HR: 1.93, 95%CI: 1.32-4.38, P = 0.006).CONCLUSIONSerum HER2 ECD could be a highly specific surrogate biomarker for tissue HER2 status in gastric cancer. Optimal cut-off criteria for predicting survival should be established.

Serum NSE, MMP-9 and HER2 extracellular domain are associated with brain metastases in metastatic breast cancer patients: predictive biomarkers for brain metastases?

Breast cancer (BC) is the second most common cause of brain metastases (BM). Predictive factors for BM have been widely studied in metastatic BC; however, there is no known serum tumor marker to accurately predict BM. Elevated serum S100ß protein and neuron-specific enolase (NSE) could reflect the brain damages induced by BM. Matrix metalloproteinase 9 (MMP-9) is involved in tumor invasion and metastatic dissemination, including BM. Also, HER2-amplified BC were shown to have a particular tropism for central nervous system (CNS). This study evaluated the correlation of these biomarkers with the presence of BM in metastatic BC patients. In this case-control study, 88 consecutive metastatic BC patients with BM (BM group) treated in our institution (2008-2015) were retrospectively selected, based on the availability of frozen serum samples for tumor marker determination. Patients were matched by age, tumor biology and number of previous metastatic chemotherapy lines to 162 metastatic BC patients without CNS involvement (control group). Serum NSE, MMP-9 and HER2 extracellular domain (ECD) levels were significantly higher in the BM group (p = 0.0051, p = 0.0062 and p = 0.0057, respectively). In multivariate analysis, serum HER2 and MMP-9 levels accurately discriminated patients with BM: odds ratios 4.4 (p < 0.001; 95%CI: 1.9-9.6) for HER2 ECD and 3.5 (p = 0.005; 95%CI: 1.5-8.4) for MMP-9. In multivariate analysis, HER2 ECD and NSE serum levels were independent prognostic factors in patients with BM. Serum HER2 ECD and MMP-9 appear to be associated with BM in metastatic BC patients. Their predictive value for BM still needs to be evaluated in further prospective studies.

Serum HER2 extra-cellular domain, S100ß and CA 15-3 levels are independent prognostic factors in metastatic breast cancer patients.

BackgroundMetastatic breast cancer (MBC) prognosis is highly variable, depending on various factors such as the biological subtype, the performance status, disease extension…. A better evaluation of a patient’s prognostic factors could allow for a more accurate choice of treatments. The role of serum tumor markers remains, however, unclear in this population. Considering the recent interest in phenotypic changes and tumor heterogeneity during breast cancer progression, additional tumor markers could be interesting in this setting.MethodsTwo hundred fifty MBC patients treated at the Montpellier Cancer Institute (2008–2015) were retrospectively selected, based on the availability of frozen serum samples. The usual MBC clinical and pathological variables were collected, altogether with Cancer Antigen 15-3 (CA15-3), Carcinoembryonic Antigen (CEA), HER2 extra-cellular domain (ECD), Neuron Specific Enolase (NSE), S100ß protein and Matrix Metalloproteinase 9 (MMP-9) serum levels in order to determine their prognostic value.ResultsWith a median follow-up of 40.8 months, median overall survival was 16.2 months (95 % CI 12.4–20.6). In multivariate analysis, the performance status, brain or subcutaneous metastases, the number of previous metastatic chemotherapy lines and the tumor biological subtype were independent prognostic factors. Elevated CA 15-3 (HR = 1.95, IC 95 % 1.31–2.93, p = 0.001), HER2 ECD (regardless of tumor HER2 status, HR = 2.51, IC 95 % 1.53–4.12, p < 0.001) and S100ß (HR = 1.93, IC 95 % 1.05–3.54, p = 0.033) serum levels were independently associated with a poor outcome.ConclusionsSerum CA 15-3, HER2 ECD and S100ß could represent useful independent prognostic factors in MBC. Of particular interest is the independent value of serum HER2 ECD levels, regardless of the tumor HER2 status, possibly linked to metastatic tumor heterogeneity.

Serum HER2 extracellular domain levels and HER2 circulating tumor cell status in patients with metastatic breast cancer.

To shed light on the clinical role of HER2 status in serum as extracellular domain (ECD) and corresponding circulating tumor cells (CTCs) in metastatic breast cancer patients. 68 patients were analyzed. Serum HER2 was determined by ADVIA Centaur(®) Serum HER2 test. CellSearch System was performed for CTC quantification. HER2 was overexpressed in 21 primary tumors. In total, 19 patients had ECD >15 ng/ml (the cut-off used), 48 patients had at least one CTC. ECD positivity was associated with CTC number (p = 0.01), HER2-positive CTC (p = 0.01) and the ratio HER2-positive CTC/total CTC (p = 0.02). ECD was not associated with survival. ECD in combination with HER2 CTC status would deserve further investigation in larger series for addressing its putative prognostic relevance.

Meaningful interpretation of serum HER2 ECD levels requires clear patient clinical background, and serves several functions in the efficient management of breast cancer patients

BackgroundThis study was initiated to evaluate the clinical significant of HER2 extracellular domain (ECD) in the real-time management of breast cancer patients. MethodsFive-hundred forty-six eligible breast cancer patients were divided according to their clinical background. The correlation between ECD, tissue HER2, and clinical outcome of the patients were analyzed. ResultsReceiver operating characteristic analysis revealed that ECD measured before receiving neoadjuvant therapy yielded the highest area under the curve (0.9185; P<0.0001), indicating that ECD and tissue HER2 levels are consistent in untreated tumor-bearing patients. At cut-off of 15.0ng/ml, the prognostic value of ECD was demonstrated using univariate (HR=1.664, P<0.0001) and multivariate (HR=1.547, P=0.011) Cox regression analysis. Kaplan-Meier survival curves revealed that patients with elevated ECD had shorter progression-free survival (PFS) (4.0 vs. 6.1months, P<0.0001). Elevated ECD was also an adverse predictor for PFS in response to anti-HER2 therapy (4.3 vs. 10.2months, P=0.0155). In contrast, ≥20%, decreased ECD was associated with longer PFS in patients who received anti-HER2 therapy (10.9 vs. 2.4months, P=0.0164) and overall (10.7 vs. 2.8months, P=0.0034). ConclusionsA patient's clinical history can help determine whether ECD could provide added value for breast cancer management.

P1-5-61 - Characterization of serum HER2 extracellular domain (ECD) level in patients with metastatic colorectal cancer

Background: Overexpression of human epidermal growth factor receptor (HER) 2 occurs in approximately 20% of breast or gastric, and 5% of colorectal cancers. Moreover,activation of the HER2 pathway has been reported to be one of the mechanisms of primary or acquired resistace to anti-EGFR antibodies in RAS wild-type metastatic colorectal cancer (mCRC). The serum level of the HER2 extracellular domain (ECD) is used as a tumor marker or surrogate marker of the HER2 status in gastric and breast cancers. However, little is known about HER2-ECD levels and its characterization in mCRC patients (pts).Methods: We prospectively analyzed consecutive mCRC pts receiving palliative chemotherapy in our hospital. HER2-ECD level was measured in blood serum, and its positivity was defined as a serum HER2 level> 15.2 ng/ml, based on the manufacturers' recommended cutoff value.Results: A total of 145 pts were enrolled in this study. Pt characteristics were as follows: males/females (55%/45%), median age (range); 64 (24- 93) years, primary site; colon/rectum (52%/48%), RAS status; wild/RAS mutant/BRAF mutant/ unknown (57%/31%/5%/8%). The positive rate of HER2 ECD, CEA, and CA19-9 were 27.6, 80.0 and 51.7%, respectively. HER2 ECD showed a linear relationship with CEA level (correlation coefficient of 0.677). Regarding the association with the RAS status, serum levels of HER2 ECD in RAS wild type pts were higher than those in RAS mutant pts (positive rate of 33 vs. 20%, respectively). Moreover, in RAS wild type pts, pts resistant to anti-EGFR antibody within 1 year showed a higher positive rate of HER2 ECD than the others (55 vs. 28%,respectively; p = 0.0311).Conclusions: A Non negligible number of mCRC pts were positive for serum levels of HER2 ECD. HER2 ECD may be associated with tumor burden and acquired resistance to anti-EGFR therapy, but further studies are necessary to determine clinical utility of HER2 ECD. Background: Overexpression of human epidermal growth factor receptor (HER) 2 occurs in approximately 20% of breast or gastric, and 5% of colorectal cancers. Moreover,activation of the HER2 pathway has been reported to be one of the mechanisms of primary or acquired resistace to anti-EGFR antibodies in RAS wild-type metastatic colorectal cancer (mCRC). The serum level of the HER2 extracellular domain (ECD) is used as a tumor marker or surrogate marker of the HER2 status in gastric and breast cancers. However, little is known about HER2-ECD levels and its characterization in mCRC patients (pts). Methods: We prospectively analyzed consecutive mCRC pts receiving palliative chemotherapy in our hospital. HER2-ECD level was measured in blood serum, and its positivity was defined as a serum HER2 level> 15.2 ng/ml, based on the manufacturers' recommended cutoff value. Results: A total of 145 pts were enrolled in this study. Pt characteristics were as follows: males/females (55%/45%), median age (range); 64 (24- 93) years, primary site; colon/rectum (52%/48%), RAS status; wild/RAS mutant/BRAF mutant/ unknown (57%/31%/5%/8%). The positive rate of HER2 ECD, CEA, and CA19-9 were 27.6, 80.0 and 51.7%, respectively. HER2 ECD showed a linear relationship with CEA level (correlation coefficient of 0.677). Regarding the association with the RAS status, serum levels of HER2 ECD in RAS wild type pts were higher than those in RAS mutant pts (positive rate of 33 vs. 20%, respectively). Moreover, in RAS wild type pts, pts resistant to anti-EGFR antibody within 1 year showed a higher positive rate of HER2 ECD than the others (55 vs. 28%,respectively; p = 0.0311). Conclusions: A Non negligible number of mCRC pts were positive for serum levels of HER2 ECD. HER2 ECD may be associated with tumor burden and acquired resistance to anti-EGFR therapy, but further studies are necessary to determine clinical utility of HER2 ECD.

Predictive value of serum HER2 ECD in patients with HER2-positive advanced gastric cancer treated with trastuzumab plus chemotherapy.

The levels of serum HER2 extracellular domain (ECD) are highly correlated with tissue HER2 status in metastatic gastric cancer (AGC). We sought to explore whether serum HER2 ECD could predict the efficacy of trastuzumab-treated HER2-positive AGC. From 2011 to 2013, trastuzumab-treated AGC patients were enrolled. Serum HER2 ECD was centrally measured by chemiluminescence immunoassays (CLIA) method in available samples at baseline and after two cycles of trastuzumab combined with chemotherapy. The correlation between serum HER2 ECD and overall response rate (ORR) and progression-free survival (PFS) was analyzed. Sixty-five patients were analyzed with a median age of 58 years (range, 27-80 years). A significant difference of serum HER2 ECD levels was found between patients with HER2 IHC 3+ and those with HER2 IHC 2+ and FISH positive (p = 0.014). There was a significantly better ORR (80.00 vs. 50.00 %, p = 0.017) and PFS (median PFS, 268 vs. 139 days, p = 0.039) for patients with abnormal baseline serum HER2 ECD than for patients with normal serum HER2 ECD. Change in serum HER2 ECD during chemotherapy was significantly correlated with response to chemotherapy (79.17 vs. 51.52 %, p = 0.033) and PFS (median PFS, 303 vs. 147 days, p = 0.005) in patients with HER2-positive tumor tissue. Our results support the clinical utility of measuring serum HER2 ECD levels in patients with advanced gastric cancer. Baseline and early changes in serum HER2 ECD could be useful for monitoring clinical outcome in HER2-positive AGC patients receiving trastuzumab-combined chemotherapy.

Is serum HER2-ECD testing significant for resectable gastric cancer?

48 Background: Accurate assessment of human epidermal growth factor receptor (HER) 2 is essential for patients with gastric cancer (GC) who may benefit from therapies targeting this surface receptor such as trastuzumab. The extracellular domain (ECD) of the HER2 protein may be shed into the serum and is detectable using an enzyme-linked immunosorbent assay. Correlations have been reported between raised baseline ECD levels, suggesting that serum ECD levels may be useful in making treatment decisions in patients with HER2 positive GC. We investigated this relationship in patients with resectable GC. Methods: This retrospective study was conducted in 71 patients with resectable GC between Apr. 2009 and May 2012. We assessed HER2 protein overexpression and gene amplification using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). HER2 positive was defined as IHC 3+ or IHC 2+/ positive FISH. The serum HER2-ECD level was measured using the blood serum before the surgical treatment. We examined the relationship between serum HER2-ECD level, HER2 expression in resected specimens, depth of invasion of cancer, lymph node metastasis, and clinical stage. Results: Baseline values were available in 71 patients, and of these, 2 (2.8%) had raised levels (&gt; 15 ng/mL). Median serum ECD levels was 11.7 (7.5-17.9) ng/mL. Two patients showing high HER2-ECD without HER2 over-expression. No clear relationship was found between baseline ECD levels and HER2 over-expression. Serum HER2-ECD level was not associated with invasion depth and lymph node metastasis, and clinical stage. Conclusions: There is no significance of serum HER2-ECD testing in resectable gastric cancer.

Preoperative serum HER2 extracellular domain levels in primary invasive breast cancer.

BackgroundDespite the preclinical outcomes and biologic significance of the presence of the human epidermal growth factor receptor-2 (HER2) extracellular domain (ECD), there is little evidence supporting the measurement of ECD levels in any clinical setting. The aim of this study was to determine the prevalence of elevated serum HER2 ECD levels, the association between these levels and tissue HER2 overexpression, and the potential clinical prognostic value of HER2 ECD in primary invasive breast cancer.MethodsSerum HER2 ECD levels were examined preoperatively in 2,862 consecutive stage I–III primary breast cancer patients between 2007 and 2009. Serum HER2 ECD levels were measured by chemiluminescence immunoassay (ADVIA Centaur), and the tissue HER2 status was assessed by immunohistochemistry and fluorescence in situ hybridization. The cutoff value for the serum level of HER2 ECD was set at 15.2 ng/ml.ResultsAmong the 2,862 patients, 126 (4.4%) had elevated serum HER2 ECD levels, and HER2 was overexpressed in the tumor tissue of 692 patients (24.2%), with a concordance of 78.7%. Multivariate analysis revealed that elevated serum HER2 ECD was a significant independent prognostic factor for worse distant-metastasis-free survival [DMFS; hazard ratio (HR) = 2.50, 95% confidence interval (CI) = 1.5–4.3, P = 0.001] and breast-cancer-specific survival (BCSS; HR = 2.0, 95% CI = 1.1–3.8, P = 0.036), which were much stronger in patients with tissue HER2-positive tumors (DMFS: HR = 3.8, 95% CI = 2.0–7.0, P < 0.001; BCSS: HR = 2.6, 95% CI = 1.2-5.3, P = 0.012).ConclusionsGiven the prevalence of HER2 expression, its measurement as an independent prognostic factor can be clinically useful, particularly in patients with tissue HER2-positive tumors.