Serum HER2 Extracellular Domain Levels Research Articles

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.

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.

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 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.

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.

P3–047 - Serum HER2ECD Levels in Patients with Advanced Gastric Cancer Treated with Trastuzumab as First-Line Therapy

Background: The ToGA study showed that trastuzumab provides a survival benefit in patients with human epidermal growth factor receptor 2 (HER2) positive unresectable or metastatic gastric cancer. Although it has been reported that serum HER2 extracellular domain (HER2ECD) was a useful tumor marker in patients with breast cancer, it remains unknown in patients with advanced gastric cancer. The purpose of this study is to evaluate the efficacy of trastuzumab in combination chemotherapy and usefulness of measurement of HER2ECD levels. Methods: We retrospectively analyzed 12 patients who were treated with first-line trastuzumab in combination of chemotherapy in our hospital. Serum HER2ECD, CEA, and CA19-9 levels at baseline and 1 to 3 months after the initiation of chemotherapy were studied. Results: The patients enrolled in this study included 9 males and 3 females, with a median age of 71 years (range, 59-84). Five patients were in PS of 0, four patients were of 1, three patients of 2. Abnormal serum HER2ECD levels were found in 75%, CEA in 83%, CA19-9 in 67% of the patients. All of three tumor markers showed high levels in six patients. In two patients, CEA and CA19-9 levels were normal, but only serum HER2ECD levels were abnormal. SP (S-1/CDDP) regimen was combined with trastuzumab in 5, XP (capecitabine/CDDP) regimen in 4, S-1 alone in 3 patients. Tumor response was evaluated in 10 patients. Four patients had PR, 5 had SD, 1 had PD, and disease control rate was 90%. Among 9 patients who showed high levels of serum HER2ECD at baseline, 7 patients were evaluated after the initiation of trastuzumab. Serum HER2ECD levels decreased 19% in five patients who had SD. In contrast, it decreased 79% in two patients who had PR. Conclusion: The efficacy of chemotherapies with trastuzumab may correlate serum HER2ECD levels, though it should be evaluated in a larger prospective study.

O1–002 - Serum HER2 Extracellular Domain Levels and Tissue HER2 Overexpression in Advanced Gastric Cancer Patients

Background: Overexpression of human epidermal growth factor receptor 2 (HER2) is now a crucial biomarker when applying the first line combination chemotherapy containing trastuzumab. Reportedly, tissue HER2 status in gastric cancer shows intra-tumor heterogeneities as well as defferences in results between facilities. In addition, though usefulness of monitoring serum HER2 extracellular domain (HER2ECD) level in metastatic breast cancer has previously reported, little is known about that of gastric cancer. In this study, firstly, we elucidated the tissue HER2 status of inoperable gastric cancers in our hospital. Secondly, we aimed to study the relationship between serum HER2ECD levels and tissue HER2 overexpression in a subset of this cohort. Methods: 1) HER2 status of gastric cancer tissues from 85 patients were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) assays in our institution. In 27 patients (Subset A) enrolled in a multi-institutional observational study, tissue HER2 status was independently examined in the other laboratory. 2)In 54 patients (Subset B), serum HER2ECD levels were measured by chemiluminescent immunoassay. Results: Tissue expression of HER2 was positive (IHC3+, or IHC2+ plus FISH+) in 15.0% (13/85) in total, 25.9% (7/27) in subset B, and 24.0 % (13/54) in subset C. One difference in results between laboratories was observed. In subset C, the mean serum HER2ECD level was 19.1 ± 25.1 ng/ml ( 11.3 ± 3.9 ng/ml for tissue HER2 negative, 44.3 ± 43.4 ng/ml for positive pts.). With a cutoff level of 15 ng/ml, the sensitivity of serum HER2ECD levels with respects to HER2 positivity was 77%, specificity 80%, positive predictive value 55.5%, negative predictive value 91.2%. Conclusion: 1) Percentage of HER2 positive metastatic gastric cancer in our institution is almost the same with previous reports, exhibiting some intra-tumor heterogeneities. 2) Although in the small and rather biased population, serum HER2ECD level shows considerable correlation with HER2 overexpression in advanced gastric cancers, warranting a further study about usefulness HER2ECD monitoring during treatment with trastuzumab.

O1–003 - Serum HER2 in Gastric Cancer

Objectives: Recent studies have demonstrated intratumoral HER2 heterogeneity of gastric cancer, thus accurate HER2 assessment is required. Serum HER2 extracellular domain level has been studied in breast cancer but its impact on cancer management remains unclear. We have been conducting a prospective multicenter study to elucidate clinical significance of serum HER2 in gastric cancer.

Abstract P4-09-09: Circulating HER2 extracellular domain (ECD) levels are associated with progression-free survival in metastatic breast cancer patients

Abstract Background: The human epidermal growth factor (HER2/neu) oncoprotein is composed of an intracellular tyrosine kinase portion, a short transmembrane section, and an extracellular ligand-binding domain (ECD). The latter is frequently cleaved from the surface of breast cancer cells and the serum HER2 ECD levels can be detected by enzyme-linked immunosorbent assay (ELISA). Consistent with majority of reports, our prior study showed that high circulating levels of the HER2 ECD indicates poor prognosis in 207 patients with metastatic breast cancer. In the present study, we aimed to elucidate whether serum HER2 ECD levels would predict the clinical outcome of metastatic breast cancer patients. Methods: Till May 19, 2012, one hundred ninty metastatic breast cancer patients were followed up. Serum was available from 190 patients at baseline, 46 patients in the assessment of time. Serum HER2 ECD levels were measured by ELISA. Disease state was assessed using Response Evaluation Criteria in Solid Tumors (RECIST). Progression-free survival (PFS) was defined as the interval from the time of randomization until the first documentation of disease progression or death due to any cause. PFS and median PFS were generated by Kaplan-Meier spots. Results: Elevated baseline HER2 ECD levels (bECD) (≥15 ng/ml) were observed in 40% (40/100) of patients with HER2-amplified tumors and 21.8% (19/87) of patients with HER2-negative tumors. Patients with bECD-elevated disease had a median PFS of 356 days compared with 229 days for patients with bECD-low disease(P = 0.001). In HER2-amplified cohort, median PFS for patients with low bECD levels was longer than those with bECD-elevated disease (391 days v 226 days, P = 0.005). And patients with low bECD levels treated with Herceptin-based regimen (n = 36) had a trend of longer PFS than patients(n = 24) treated with non-Herceptin regimen(447 days v 298 days, P = 0.227). Moreover, bECD-low patients (n = 36) showed a significantly longer median PFS than bECD-elevated patients(n = 22) when treated with Herceptin-based scheme (447 days v 229 days, P = 0.004). While, in patients with increased bECD levels, there was no statistical difference between Herceptin-treated groups (n = 22) and non-Herceptin-treated groups (n = 14) (229 days v 173 days, P = 0.761). In the HER2-negative group, patients with bECD-low disease had a median PFS of 313 days compared with 206 days for patients with bECD-elevated disease (P = 0.02). In a cohort of 46 patients whose HER2 ECD levels were monitored during treatment, 29 patients remains low ECD levels, 12 patients convert from elevated to low, 2 patients convert from low to high, and 3 patients remains elevated HER2 ECD levels. The patients who remained low ECD levels or achieved low ECD leves have significantly longer PFS than those whose levels remained above 15ng/mL or converted from low to high regardless of treatment given (440 days v 192days, P = 0.019). Conclusion: Elevated HER2 bECD predicts poor median PFS irrespective of HER2 status. HER2-amplified patients with low-HER2 ECD levels may get more benefit from Herceptin-based scheme. Remained low-HER2 ECD levels or decreases in serum HER2 ECD levels during treatment were associated with longer median PFS in metastatic breast cancer. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-09-09.

Abstract P2-05-05: Circulating HER2 extracellular domain (ECD) predicts a poor prognosis for metastatic breast cancer patients

Abstract Background: Amplification or overexpression of HER2 has been shown to play an important role in approximately 30% of breast cancers and is strongly associated with increased recurrence and a worse prognosis. The HER2 extracellular domain (ECD) may be cleaved and shed from the surface of breast cancer cells and serum HER2 ECD levels can be detected by enzyme-linked immunosorbent assay (ELISA). In this study, we explored the relationship between circulating HER2 ECD and tissue HER2 status, then we also examined its predictive value in a cohort of metastatic breast cancer patients. Methods: Two hundred and seven metastatic breast cancer patients from March 2009 to July 2011 were involved in this prospective study at Zhejiang Cancer Hospital. The patients were identified histopathologically as having breast cancer by pathologists and staged mainly based on the pathology, the clinical manifestation, and the imaging findings of CT and MRI according to the classification system of the International Union Against Cancer. Serum HER2 ECD levels were measured by ELISA. Tissue HER2 was determined by IHC and FISH in tumor samples, respectively. Results: The level of serum HER2 ECD was at least more than 15 ng/ml in 31.4% (65/207) metastatic breast cancer patients, 39.1%(43/110) in HER2-positive patients and 23.4%(22/94) in HER2-negative cases, respectively, P = 0.017. We also found that high serum HER2 ECD levels (≥15 ng/ml) were significantly associated with elevated serum CEA (52.1% v 21.5%, OR 3.978, 95%CI 2.138–7.401, P = 0.000), CA125 (48.5% v 23.5%, OR 3.064, 95%CI 1.650–5.691, P = 0.000), CA153 (53.2% v 17.1%, OR 5.48, 95%CI 2.897–10.366, P = 0.000), LDH (53.3% v 23.1%, OR 3.798, 95%CI 2.011–7.173, P = 0.000) and AKP (51.2% v 26.5%, OR 2.911, 95%CI 1.442–5.879, P = 0.002), respectively. For the effect of HER2 ECD on the site of relapse, still there were statistically significant correlation between increased serum HER2 ECD levels and liver involvement (42.7% v 24.0%, OR 2.358, 95%CI 1.294–4.297, P = 0.005), brain metastasis (50.0% v 26.7%, OR 2.744, 95%CI 1.397–5.391, P = 0.003) and visceral involved (37.9% v 14.8%, OR 3.511, 95%CI 1.548–7.961, P = 0.002), respectively. While serum HER2 ECD levels were not related to age, BMI, tumor size, lymph node involvement and hormone receptors status, respectively (P&amp;gt;0.05). Conclusions: Monitoring the circulating levels of the HER2 ECD in patients with metastatic breast cancer provides a real-time assessment of tumor burden and indicates poor prognosis, and may provide important information for reassessment of HER2 in HER2-negative metastatic breast cancer. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-05-05.

302 - Study on Serum HER2 Extracellular Domain Expression in Early Stage Breast Cancer Patients

ABSTRACT Background The measurement of the human epidermal growth factor receptor 2 (HER2) protein in the serum of metastatic breast cancer patients has now been reported, but there are no consistent data to support the clinical utility of serum HER2 extracellular domain (ECD) for patients with early breast cancer. We aimed to evaluate the correlation between serum HER2 ECD levels and tumor HER2 status, and analyze their relationship with clinicopathological parameters in patients with early stage disease. Methods A prospective study was conducted on 232 breast cancer patients with stage I-II diseases before treatment. Preoperative serum samples were measured by enzyme-linked immunosorbent assay (ELISA). Tissue HER2 status was analyzed by immunohistochemistry and fluorescence in situ hybridization assays. Results The median serum HER2 ECD concentration was 6.8 ng/ml (range 1.3 - 42.1 ng/ml). The best diagnostic cut-off value was 7.4 ng/ml (with 72.9% sensitivity and 85.3% specificity), which was lower than HER2 ECD cut-off value with metastasis breast cancer (15 ng/ml). High serum HER2 ECD levels were reported in 89 patients (38.3%) and HER2 tissue positive expression was observed in 77 patients (33.2%) with a moderate concordance of 76.7%. Elevated serum HER2 ECD correlated with postmenopausal (p Conclusion HER2 ECD, which is associated with poor prognosis, may provide more additional information compared with HER2 tissue alone. We support that it is necessary to decrease the cut-off value in evaluating serum HER2 ECD level for early stage breast cancer. Disclosure All authors have declared no conflicts of interest.

Comparison between HER2 extracellular domain in serum and HER2 overexpression in breast cancer tissue.

e11066 Background: Immunohistochemistry (IHC), fluorescent in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) are reliable ways to identify human epidermal growth factor receptor 2 (HER2) and HER2 amplification. Each technique requires access to tumor tissue and high-quality tissue sample, which may not be available in some patients. HER2 extracellular domain (ECD) may be shed to the serum. The importance of serum ECD in breast cancer (BC) is not yet determined. The first aim of this study was to explore the correlation between serum ECD and HER2 expression in breast cancer tissue. The second aim was to compare ECD levels with clinical and pathological features in early BC patients. Methods: This prospective trial included patients with stage I–III BC. Serum HER2 ECD levels were measured by ADVIA Centaur automated assays before surgical resection of the tumor. Tissue HER2 status was detected by IHC in all tumors. CISH test was utilized in HER2: +2 tumors by IHC. Serum ECD >15ng/ml w...

198 Evaluation of serum HER2 extracellular domain levels in patients with metastatic breast cancer and those who underwent preoperative systemic treatment

A hybrid pharmacophore approach was used to design and synthesize isatin–benzothiazole analogs to examine their anti-breast cancer activity. The cytotoxicity of these compounds were determined using three different human breast tumor cell lines, MDA-MB231, MDA-MB468, MCF7, and two non-cancer breast epithelial cell lines, 184B5 and MCF10A. Although all compounds examined were quite effective on all the cancer cell lines examined, the compounds 4-bromo-1-diethylaminomethyl-1H-indole-2,3-dione (2l) and 4-chloro-1-dimethylaminomethyl-3-(6-methyl-benzothiazol-2-ylimino)-1,3-dihydro-indol-2-one (5e) emerged as the most active compounds of this series. Importantly, the cytotoxic effect of 2l was 10–15-fold higher on cancer than non-cancer cells, suggesting that this compound can be very effective for the control of breast cancer with low side effects. Since 2l showed effective cytotoxicity on MCF7 cells and arrested the cells at G2/M at a similar concentration, these two phenomena may be closely correlated. We conclude that the isatin-linked benzothiazole analog can serve as a prototype molecule for further development of a new class of anti-breast cancer agents.

Utility of Serum HER2 Extracellular Domain Assessment in Clinical Decision Making: Pooled Analysis of Four Trials of Trastuzumab in Metastatic Breast Cancer

Trastuzumab is a humanized monoclonal antibody directed against human epidermal growth factor receptor 2 (HER2). Trastuzumab alone or in combination with chemotherapy has been shown to be effective in patients with HER2-positive early and metastatic breast cancer. 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 and response to trastuzumab, suggesting that serum ECD levels may be useful in making treatment decisions in patients with HER2-positive breast cancer. We investigated this relationship, and also the effect of trastuzumab and chemotherapy on ECD levels, in patients with advanced breast cancer. This study analyzed sequential ECD determinations on 322 patients treated with six different treatment regimens in four clinical trials. Baseline values were available in 296 patients, and of these, 205 (69%) had raised levels (> 15 ng/mL). No clear relationship was found between baseline ECD levels and tumor response. After initiating combination therapy, ECD levels declined irrespective of treatment received and tumor response. For trastuzumab monotherapy, some trend between changes in ECD levels in early cycles and best response was discernable, but the overlap was too broad to be clinically useful. Disease progression was not reliably predicted by rising ECD levels in the majority of patients. Based on our data, we cannot recommend using serum HER2 ECD levels to make trastuzumab or other treatment decisions for individual patients with advanced/metastatic breast cancer.

Kinetics of serum HER‐2/neu changes in patients with HER‐2‐positive primary breast cancer after initiation of primary chemotherapy

The purpose of the study was to determine the utility of quantitation of the extracellular domain (ECD) of the HER-2/neu receptor in the serum for predicting response to treatment in patients with primary breast cancer receiving neoadjuvant therapy. HER-2/neu ECD was measured in sera obtained from 39 patients with HER-2-amplified stage II-III primary breast cancer undergoing neoadjuvant chemotherapy. Patients were randomly assigned to either 4 cycles of paclitaxel followed by 4 cycles of fluorouracil, epirubicin, and cyclophosphamide (FEC) (n = 10) or to the same chemotherapy with simultaneous weekly trastuzumab for 24 weeks (n = 29). Changes in HER-2 ECD were monitored with the Bayer HER-2/neu assay over 6 months and correlated with pathological response to treatment. Before initiation of chemotherapy, 28.2% of patients had elevated concentration of the HER-2 ECD (>15 ng/mL). The median baseline serum HER-2 ECD concentration was 13.6 ng/mL (mean +/- SD, 20.3 +/- 35.5 ng/mL). A decrease in the median HER-2 ECD levels from baseline to Week 3 and from baseline to Week 6 of chemotherapy was seen regardless of treatment regimen. No significant difference in baseline HER-2 ECD levels was observed between the groups who achieved pathological complete response (pCR) and the group with residual disease (P = .41). However, a 9% drop from Week 3 to Week 6 after initial chemotherapy was predictive of pCR (P = .04). A decrease in serum HER-2 ECD levels early during treatment was associated with pathological response in patients receiving primary chemotherapy, particularly trastuzumab-based regimens. Serum HER-2 ECD levels may serve to monitor neoadjuvant therapy in HER-2-positive primary breast cancer.

Docetaxel plus epirubicin as first-line chemotherapy in MBC (KCSG 01-10-05): Phase II trial and the predictive values of circulating HER2 extracellular domain and vascular endothelial growth factor

The anthracyclines and taxanes are considered to be the most active drugs in metastatic breast cancer (MBC). We conducted a multicenter phase II study to evaluate the efficacy and tolerability of the docetaxel plus epirubicin combination chemotherapy as first-line treatment in MBC and performed a prospective assessment of the predictive values of circulating HER2 extracellular domain (ECD) and vascular endothelial growth factor (VEGF). Docetaxel 75 mg/m(2) and epirubicin 75 mg/m(2) were given intravenously every 3 weeks. Prophylactic G-CSF was not used. Pretreatment serum HER2 ECD and VEGF levels were measured by enzyme immunoassay. Forty MBC patients were enrolled, and 39 patients were evaluable for toxicities and 38 for response. Complete response was observed in 3 (7.9%) patients, partial response in 20 (52.6%) (overall response rate 60.5%), stable disease in 11 (28.9%) and disease progression in 4 (10.5%). After a median follow-up of 22.5 months, the median duration of response was 28 weeks, median time to disease progression was 32 weeks, and median survival was 15.8 months. Two-hundred and fifteen cycles of treatment were administered (median, 6 cycles per patient). Grade 3 and 4 neutropenia were observed during 24 (11.2%) and 74 (35%) cycles respectively, and grade 3 or 4 febrile neutropenia in 24 (11.2%) cycles. Elevated circulating HER2 ECD levels were found to be associated with a shorter response duration (p<0.005) and shorter time to progression (p<0.005). However, elevated VEGF levels were not found to be correlated with response rate or survival. We concluded that the docetaxel and epirubicin combination is an effective first-line treatment in MBC patients and that elevated serum HER2 ECD levels, but not circulating VEGF levels, predict a poor outcome.

Serum HER2 extracellular domain in metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel: association with HER2 status by immunohistochemistry and fluorescence in situ hybridization and with response rate

PurposeWe explored the relationship between circulating HER2 extracellular domain (ECD) and tissue HER2 status as determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). We also examined its predictive value in a cohort of metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel. MethodsEligible patients had pre- and post-treatment stored serum specimens and were treated on a previously reported phase II trial. Retrospective analysis evaluated: the association between pretreatment serum HER2 ECD and tissue HER2 status by IHC and FISH; and the association between change in serum HER2 ECD after 12 weeks of therapy and response proportion. ResultsStored serum samples were available for 55/95 (58%) patients. Statistically significant associations were found between HER2 status as assessed by IHC and FISH, and baseline serum HER2 ECD level. Patients whose ECD normalized after 12 weeks of therapy had a higher response proportion compared with patients with persistently high ECD levels (68% versus 15%, P=0.005). A relative decline of over 55% from baseline HER2 ECD predicted response to therapy. ConclusionA statistically significant association was observed between pretreatment serum HER2 ECD and tissue HER2 status as assessed by IHC and FISH. A decrease in serum HER2 ECD level was a significant predictor of response to trastuzumab-based therapy.