• BMB Reports
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• v.51 no.12
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• pp.660-665
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• 2018

Human epidermal growth factor receptor 2 (HER2) inhibitors, such as trastuzumab and lapatinib are used to treat HER2-positive breast and gastric cancers. However, as with other targeted therapies, intrinsic or acquired resistance to HER2 inhibitors presents unresolved therapeutic problems for HER2-positive gastric cancer. The present study describes investigations with AUY922, a heat shock protein 90 (HSP90) inhibitor, in primary lapatinib-resistant (ESO26 and OE33) and lapatinib-sensitive gastric cancer cells (OE19, N87, and SNU-216) harboring HER2 amplification/over-expression. In order to investigate whether AUY922 could overcome intrinsic and acquired resistance to HER2 inhibitors in HER2-positive gastric cancer, we generated lapatinib-resistant gastric cancer cell lines (OE19/LR and N87/LR) by continuous exposure to lapatinib in vitro. We found that activation of HER2 and protein kinase B (AKT) were key factors in inducing intrinsic and acquired lapatinib-resistant gastric cancer cell lines, and that AUY922 effectively suppressed activation of both HER2 and AKT in acquired lapatinib-resistant gastric cancer cell lines. In conclusion, AUY922 showed a synergistic anti-cancer effect with lapatinib and sensitized gastric cancer cells with intrinsic resistance to lapatinib. Dual inhibition of the HSP90 and HER2 signaling pathways could represent a potent therapeutic strategy to treat HER2-positive gastric cancer with intrinsic and acquired resistance to lapatinib.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1981-1984
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• 2013

Objective: The optimal duration of adjuvant trastuzumab treatment in patients with HER2-positive breast cancer is not known. The aim of this study was to evaluate the efficacy of 6 months of adjuvant trastuzumab treatment in patients with stage II or III HER2-positive breast cancer. Methods: The records of patients with HER2-positive stage II or III breast cancer who were admitted to the Breast Center of Taipei Medical University Hospital and Yuan's General Hospital between 2000 and 2008 were reviewed. All patients received adjuvant trastuzumab at an initial dose of 4 mg/kg followed by a maintenance dose of 2 mg/kg/week for 22 weeks in combination with chemotherapy. Results: A total of 51 patients were included with a mean age of 46.9 years. Approximately 55% of the patients had stage III disease. The mean follow-up time from initiation of treatment was 45.2 months (range, 0.9 to 85 months). During follow-up, 46 patients (90.2%) did not experience tumor recurrence. The mean estimated disease free survival was 80.2 months. The estimated 1-, 2-, 5-, and 7-year survival rates were 97.9%, 93.1%, 93.1%, and 93.1%, respectively. The most common adverse effects were gastrointestinal symptoms (21.6%), chills (17.6%), dizziness (9.8%), and bone pain (7.8%). No cardiac or hematologic adverse events occurred. Conclusion: Adjuvant therapy with trastuzumab for 6 months resulted in a clinical benefit in patients with HER2-positive breast cancer.

• Journal of Gastric Cancer
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• v.23 no.1
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• pp.224-249
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• 2023

Gastric cancer is heterogeneous in morphology, biology, genomics, and treatment response. Alterations in human epidermal growth factor receptor 2 (HER2) overexpression, microsatellite instability (MSI) status, programmed death-ligand 1 (PD-L1) levels, and fibroblast growth factor receptor 2 (FGFR2) can be used as biomarkers. Since the combination of fluoropyrimidine/platinum plus trastuzumab that was investigated in the ToGA trial was approved as a standard of care in HER2-positive patients in 2010, no other agents showed efficacy in the first- (HELOISE, LOGiC, JACOB trials) and second- (TyTAN, GATSBY, T-ACT trials) line treatments. Despite the success in treating breast cancer, various anti-HER2 agents, including a monoclonal antibody (pertuzumab), an antibody-drug conjugate (ADC; trastuzumab emtansine [T-DM1]), and a small molecule (lapatinib) failed to translate into clinical benefits until the KEYNOTE-811 (first-line) and DESTINY-Gastri01 (≥second-line) trials were conducted. The incorporation of HER2-directed treatment with immune checkpoint inhibitors in the form of a monoclonal antibody or ADC is now approved as a standard treatment. Despite the promising results of new agents (engineered monoclonal antibodies, bi-specific antibodies, fusion proteins, and small molecules) in the early phase of development, the management of HER2-positive gastric cancer requires further optimization to achieve precision medicine with a chemotherapeutic backbone. Treatment resistance is a complex process that can be overcome using a combination of chemotherapy, targeted agents, and immune checkpoint inhibitors, including novel agents. HER2 status must be reassessed in patients undergoing anti-HER2 treatment with disease progression after the first-line treatment. As a general guideline, patients who need systemic treatment should receive chemotherapy plus targeted agents, anti-angiogenic agents, immune checkpoint inhibitors, or their combinations.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5539-5544
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• 2014

Background: To evaluate the location of tumor relapse and imaging modality for detection according to the breast cancer subtype: luminal A, luminal B, HER2 positive luminal B, nonluminal HER2 positive, and triple negative. Materials and Methods: A total of 1244 patients with breast cancer with known estrogen receptor (ER), progesterone receptor (PR), Ki-67 and human epidermal growth factor receptor 2 (HER2), who underwent breast surgery from 2009 to 2012 were analyzed. Patients were classified into the following categories: luminal A (n=458), luminal B (n=241), HER2 positive luminal B (n=227), nonluminal HER2 positive (n=145) and triple negative (n=173). A total of 105 cases of relapse were detected in 102 patients: locoregional recurrence (n=46), recurrence in the contralateral breast (n=28) and distant metastasis (n=31). Comparison of proportions was used to determine the difference between subtypes. Results: Relapse rates by subtypes are as follows: luminal A 23 of 458 (5.02%), luminal B 19 of 241(7.88%), HER2 positive luminal B 15 of 227 (6.61%), nonluminal HER2 postive 19 of 145 (13.10%) and triple negative 29 of 173(16.76%). Luminal A tumors had the lowest rate of recurrence and had significantly lower recurrence rate in comparison with nonluminal HER2 postive (p=0.0017) and triple negative subtypes (p<0.0001). Compared with all other subtypes except nonluminal HER2 positive, triple negative tumors had the highest rate of tumor recurrence (p<0.01). Triple negatives were most likely to develop contralateral recurrence against all subtypes (p<0.05). Detection rate of locoregional and contralateral tumor recurrence were 28.3% on mammography (n=17/60). Conclusions: Luminal A tumors are associated with a low risk of recurrence while triple negative lesions have a high risk. In case of triple negative tumors, the contralateral breast has much more recurrence as compared with all other subtype. In terms of detection rates, breast USG was the best modality for detecting tumor recurrence, compared with other modalities (p<0.05). Subtyping of breast tumors using a molecular gene expression panel can identify patients who have increased risk of recurrence and allow prediction of locations of tumor recurrence for each subtype.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.3903-3909
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• 2016

Purpose: To evaluate the expression of Her2/neu and Ki-67 in benign and malignant gallbladder lesions, and to establish correlations with clinico-pathologic parameters. Materials and Methods: A retrospective analysis was conducted on formalin fixed paraffin embedded (FFPE) benign (n=25) and malignant gallbladder (n=25) tissue samples. Hematoxylin and eosin stained slides of each case were reviewed for: type of malignancy (whether adenocarcinoma, squamous cell carcinoma, or any other type), grade (well, moderate, and poor), depth of invasion, pre-neoplastic changes in adjacent mucosal epithelium like metaplasia and dysplasia. Immunohistochemistry for Her 2 neu and Ki-67 was performed and data analysis was conducted using SPSS 17 software. Chi-square test was used to compare categorical/dichotomous variables. P value of ${\leq}0.05$ was considered significant. Results: The difference of Her 2 neu expression and Ki67 index between benign and malignant groups was found to be statistically significant. Her2/neu positivity did not have any significant correlation with various clinicopathological parameters other than liver involvement. 5 cases of gallbladder cancer showed both Her2/neu and Ki67 positivity. Ten cases were Ki67 positive but Her2/neu negative while one case was Her2/neu positive but Ki67 negative. Conclusions: The present study demonstrated overexpression of Her2/neu and Ki67 in gallbladder cancer. A trend of decreasing Her2/neu expression with increasing grade of tumor was observed. Furthermore, greater Ki67 positivity was found in cases with lymph node metastasis and distant metastasis. Future studies with a larger number of patients will be required to precisely define the correlation of Her2/neu expression and Ki67 positivity with clinicopathological parameters. The results however are encouraging and suggest evaluation of Her2/neu as a candidate for targeted therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7695-7700
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• 2015

Background: HER2/neu overexpression on cell membranes of breast cancer cells is due to HER2/neu gene amplification and it is important to identify potential candidates for anti HER2 therapy with trastuzumab. IHC, FISH and CISH are standard FDA approved assays currently used to determine HER2 status in routine practice. The aim of this study was to determine HER2 gene amplification, using the CISH method in breast carcinoma samples which had IHC +2 reactions. Materials and Methods: This study was conducted from 2008-2010 using 334 consecutive breast carcinoma samples referred from local laboratories to Mehr Hospital. CISH assays were performed for all cases, and IHC tests were also done for determining efficacy and accuracy of local labs. HER2 status in local IHC tests was compared with central IHC and CISH results. Results: Of 334 breast cancer patients, 16 were negative for HER2 IHC (0, +1), 201 cases were equivocal (+2), and 31 positive (+3). Of 334 referral cases, 88 were CISH positive (26.3%) and 246 were CISH negative (73.7%). Of 201 IHC +2 cases, HER2 gene amplification was observed in 42 cases (kappa: 0.42). A 29.9% concordance was found between local IHC and central IHC. Sensitivity and specificity of local IHC were 90% and 53.8%, respectively. Conclusions: Low accuracy of IHC results in local labs was associated with the following factors: using former FDA-approved criteria for HER2 interpretation, utilizing non-validated kits, and lack of any quality assurance program. Therefore, following the new 2014 ASCO/CAP guideline and comprehensive quality assurance should be implemented to ensure accuracy of HER2 testing.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.903-907
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• 2015

Background: Among human epidermal growth factor receptor 2 (HER2)-positive breast cancer, more than half are also hormone receptor (HR)-positive. Although HR is a predictive factor for the efficacy of hormone therapy, there are still some uncertainties in regard to the effects on patients with HR-positive and HER2-positive metastatic breast cancers due to the potential resistance to hormone therapy caused by co-expression of HR and HER2. There are no clinical trials directly comparing the efficacy of hormonal therapy with chemotherapy. Materials and Methods: To examine the real-world effect of hormone therapy on patients with HR-positive and HER2-positive metastatic breast cancers, a cross-sectional study of a representative sample of the Chinese population was conducted. The study included 113 patients who received first-line and second-line palliative treatment between 2005 and 2010 in the Cancer Institute and Hospital, Chinese Academy of Medical Science. The effect of hormone therapy on overall survival (OS) was studied. Results: The patients who received hormone therapy (n=51) had better overall survival in contrast to those who received chemotherapy with anti-HER2 therapy (n=62) in first- or second-line treatment. The difference was of borderline statistical significance (51.8m vs 31.9m, p=0.065). In addition, the effect of hormone therapy did not differ significantly with other prognostic factors, including age (${\leq}50$ years or >50 years), disease free survival (${\geq}2$ years or < 2 years) and site of metastasis (visceral or bone/soft tissue). On multivariate analysis, administration of hormone therapy was associated with a trend toward a favorable prognosis (p=0.148, HR=0.693, 95%CI 0.422-1.139). Age more than 50 years was the sole independent harmful prognostic factor (p<0.001, HR=2.797, 95%CI 1.676-4.668). Conclusions: Our data suggest that hormonel therapy may improve outcomes of the patients with ER-positive and HER2-positive metastatic breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2891-2896
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• 2012

Background: HER2/neu, a member of EGFR family, is over expressed in some tumors. The purpose of this study was to determine the salivary level and tissue expression of HER2/neu in patients with head and neck squamous cell carcinoma (HNSCC) and any correlation with clinicopathologic parameters. Methods: An enzyme-linked immunosorbent assay (ELISA) was used to evaluate the salivary level and immunohistochemistry (IHC) to assess tissue expression of HER2/neu in 28 patients with HNSCC and 25 healthy controls. Results: The salivary levels of HER2/neu in HNSCC patients was not significantly higher than in the healthy controls (p>0.005). There was no apparent correlation in salivary HER2/neu level with clinicopathological features such as age, sex, grade, tumor size and nodal status. All HNSCC specimens were positive (membranous or/and cytoplasmic) for HER2/neu, except one sample. Only one HNSCC specimen was stained in cytoplasm purely. All control specimens were membranous and cytoplasmic positive for HER2/neu. There was a significant difference between cytoplasmic staining in case and control groups (p-value<0.05). Conclusion: In our cases, no overexpression of HER2/neu was observed. Thus, our findings suggested that the use of Her-2 as a salivary marker of HNSCC cannot be recommended.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7111-7116
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• 2013

Introduction: Trastuzumab, an HER2-targeting agents, has shown efficacy in metastatic HER2-positive breast cancer patients. Single-agent clinical trials have evaluated therapeutic regimens using trastuzumab for metastatic breast cancer patients. The aim of our study is to evaluate the efficacy and safety of trastuzumab in combination with chemotherapy or hormone therapy in HER2-positive metastatic breast cancer patients. Methods: A literature research was conducted in PubMed and to identify appropriate studies from relevant reviews. Randomized controlled trials comparing chemotherapy or hormone therapy regimens in combination with trastuzumab were eligible. Dadta on clinical outcomes, including safety, efficacy, and patient characteristics were collected. Results: Seven articles describing five trials were included in our systematic review and meta-analysis. Partners of trastuzumab included in trials were anthracycline, paclitaxel, docetaxel, anastrozole and letrozole. The addition of trastuzumab to chemotherapy improved the overall survival (HR=0.79, 95%CI 0.65-0.96), while to hormone therapy did not (HR=0.85 95%CI 0.56-1.30). All trastuzumab-containing regimens increased cardiac toxicity (RR=3.37, 95%CI 1.26-9.02) and grade III-IV adverse events. Conclusions: Our study supports the addition of trastuzumab to chemotherapy which is effective and tolerated for metastatic breast cancer with HER2+ patients. Of note, more adverse events will occur followed the use of trastuzumab, especially cardiac toxicity, with two treatment regimens.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7597-7602
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• 2014

Background: Amplification and overexpression of human epidermal growth factor receptor 2 (HER2/neu) oncogene has considerable prognostic value in breast and gastric cancers. This study aimed to evaluate the frequency, overexpression pattern, clinical significance, and concordance between the results for protein expression and gene amplification of HER-2/neu in gastric and gastro-esophageal junction carcinomas. Materials and Methods: In this study, 101 gastric tissue samples which were included in tissue microarray were immunohistochemically examined for overexpression of HER2/neu. Chromogenic in situ hybridization (CISH) was used for HER-2/neu amplification. The correlation of HER2/neu amplification with clinicopathological parameters was also assessed. In addition, concordance between CISH and IHC was detected. Results: This study demonstrated a significant difference in the overexpression of HER2/neu in gastric tumors. The overexpression of HER2/neu was significantly higher in intestinal type, poorly differentiated grade, large size ($5cm{\leq}$) and positive nodal involvement tumors (p-value=0.041, 0.015, 0.038 and 0.071, respectively). Also, amplification of HER2/neu according to CISH test, had a significant positive correlation with tumor size and tumor type (p-value=0.018 and 0.058, respectively).Concordance between CISH and IHC was 76.9% in 101 evaluable samples. Conclusions: IHC/CISH differences were attributed to basolateral membranous immunoreactivity of glandular cells resulting in incomplete membranous reactivity and/or a higher rate of tumor heterogeneity in gastric cancers compared to breast cancers. Therefore, this can be a potential marker for targeted therapy of malignant gastric tumors.