TP53 and/or BRCA1 Mutations Based on CtDNA Analysis as Prognostic Biomarkers for Primary Triple-Negative Breast Cancer.

Precise biomarkers for predicting the therapeutic efficacy of molecularly targeted drugs are limited at the protein level; thus, it has been important to broadly scrutinize individual cancer driver gene mutations for effective cancer treatments. Multiplex cancer genome profiling can comprehensively identify gene mutations that are therapeutic targets using next-generation sequencing (NGS). In addition, circulating tumor DNA (ctDNA) is a DNA fragment released into the blood by tumor cell-derived cell death or apoptosis. Liquid biopsy with ctDNA is a novel clinical test for identifying genetic mutations in an entire population noninvasively, in real-time, and heterogeneously. Although there are several reports on ctDNA, fewer have evaluated ctDNA with NGS before an initial treatment for breast cancer patients. Therefore, we examined whether analyzing tumor-associated gene mutations in primary breast cancer based on ctDNA could serve as a biomarker for prognosis and optimal treatment selection. Ninety-five primary breast cancer patients treated at our department from January 2017 to October 2020 were included. Pretreatment plasma samples were subjected to NGS analysis of ctDNA, and correlations with patients' clinicopathological characteristics were evaluated. Fifty-nine (62.1%) patients were positive for ctDNA. ctDNA tended to be positive in hormone receptor-negative, and TP53 (34%), BRCA1 (20%), and BRCA2 (17%) gene mutations were more frequent. Regarding recurrence-free survival, the prognosis was poor in the TP53 and/or BRCA1 mutation-positive groups, especially in triple-negative breast cancer (TNBC) patients. In conclusion, the results of this study indicate that ctDNA with liquid biopsy could identify the poor prognosis group before treatment among TNBC patients and for those for whom optimal treatment selection is desirable; additionally, optimal treatment could be selected according to the ctDNA analysis results.

Granzyme B Expression in the Tumor Microenvironment as a Prognostic Biomarker for Patients with Triple-Negative Breast Cancer.

Tumor-infiltrating lymphocytes in the tumor microenvironment are important in the treatment of triple-negative breast cancer (TNBC). Cytotoxic T cells produce cytokines and cytotoxic factors, such as perforin and granzyme, which induce apoptosis by damaging target cells. To identify biomarkers of these cells, we investigated granzyme B (GZMB) in the tumor microenvironment as a biomarker of treatment response and prognosis in 230 patients with primary TNBC who underwent surgery without preoperative chemotherapy between January 2004 and December 2014. Programmed cell death ligand 1 (PD-L1) positivity was defined as a composite positive score ≥10 based on the PD-L1 immunostaining of tumor cells and immune cells. GZMB-high was defined as positivity in ≥1% of tumor-infiltrating lymphocytes (TILs). Among the 230 TNBC patients, 117 (50.9%) had CD8-positive infiltrating tumors. In the PD-L1-positive group, a Kaplan-Meier analysis showed that GZMB-high TNBC patients had better recurrence-free survival (RFS) and overall survival (OS) than GZMB-low patients and that OS was significantly longer (RFS: p = 0.0220, OS: p = 0.0254). A multivariate analysis also showed significantly better OS in PD-L1- and GZMB-high patients (hazard ratio: 0.25 (95% IC: 0.07-0.88), p = 0.03). Our findings indicate that GZMB is a useful prognostic biomarker in PD-L1-positive TNBC patients.

A novel germline mutation of TP53 with breast cancer diagnosed as Li-Fraumeni syndrome.

TP53 is a tumor suppressor gene and, when dysfunctional, it is known to be involved in the development of cancers. Li-Fraumeni syndrome (LFS) is a hereditary tumor with autosomal dominant inheritance that develops in people with germline pathogenic variants of TP53. LFS frequently develops in parallel to tumors, including breast cancer. We describe a novel germline mutation in TP53 identified by performing a multi-gene panel assay in a breast cancer patient with bilateral breast cancer.

Significance of the Multi-gene Panel myRisk in Japan.

BACKGROUND/AIM: Hereditary tumors are estimated to account for approximately 5-10% of all tumors. In Europe and the United States, multi-gene panel testing (MGPT) is the standard method used for identifying potential causative genes. However, MGPT it is still not widely used in Japan. The aim of this study was to assess the risk of hereditary tumors in Japanese cancer patients using germline MGPT and provide an overview of MGPT in the Japanese medical system. PATIENTS AND METHODS: We used the myRiskTM, a 35-gene panel that determines the risk for eight hereditary cancers: breast, ovarian, gastric, colorectal, prostate, pancreatic, malignant melanoma, and endometrial cancers. RESULTS: From June 2019 to March 2020, 21 patients who were suspected to have hereditary tumors were included, based on their family or medical history. Pathogenic variants were found in 7 patients [BRCA1 (5), MSH6 (1), TP 53 (1)]. CONCLUSION: In this study, despite the small number of participants, we were able to show the significance of MGPT in Japan. Therefore, MGPT should be used for evaluating hereditary tumors in clinical practice.

CCND1 Copy Number Variation in Circulating Tumor DNA from Luminal B Breast Cancer Patients.

BACKGROUND/AIM: Abnormalities in the cyclin D1-CDK4/6 complex have been implicated in breast cancer proliferation and resistance to treatment. Recently, new drugs have been developed to target CDK4/6. Meanwhile, liquid biopsy has received great interest in oncology. In this study, we analyzed cyclin D1 gene (CCND1) copy number variation (CNV) in circulating tumor DNA (ctDNA) from luminal B breast cancer patients. PATIENTS AND METHODS: This study included 31 patients with luminal B breast cancer who underwent resection. We analyzed CCND1 CNV in ctDNA by digital droplet PCR. RESULTS: Of the 31 luminal B breast cancers, CCND1 CNV was positive in 5 cases. Patients with CCND1 CNV positivity had significantly shorter recurrence-free survival than patients with negative CCND1 CNV. CONCLUSION: CCND1 CNV in ctDNA was associated with poor prognosis in patients with luminal B breast cancer. This biomarker could be a useful prognostic factor.

Genetic medicine is accelerating in Japan.

BACKGROUND: In 2018, BRACAnalysis® was covered by medical insurance in Japan as a companion diagnostic test for the poly ADP-ribose polymerase inhibitor olaparib. In April 2020, eligibility for BRCA1/2 genetic testing was expanded to the diagnosis of hereditary breast and ovarian cancer syndrome, and medical management including prophylactic surgery and surveillance were covered by public insurance for BRCA1/2 mutation carriers who developed breast or ovarian cancer. The amount of BRCA1/2 genetic testing has been increasing recently, but the number of subjects and the impact of testing for patients' outcomes remain unclear. PATIENTS AND METHODS: This study explored the potential number of patients who will be eligible for new insurance coverage for BRCA1/2 genetic testing. We analyzed 868 patients from 938 surgeries between January 2014 and September 2020 from our database. RESULTS: Overall, 372 patients (43%) were eligible for new insurance coverage for BRCA1/2 genetic testing. The most common category was family history of breast or ovarian cancer within third-degree relatives. We found that 202 patients (23%) had family history of breast or ovarian cancer. In addition, the progression-free survival was significantly lower in triple-negative breast cancer patients aged 60 years or younger compared with the other patients (P = 0.0005). CONCLUSION: The genetic medicine for primary breast cancer patients with BRCA1/2 germline mutation is accelerating rapidly in Japan. Therefore, establishing a system for the genetic medicine would be urgent.

Current Status and Problems of Breast Cancer Treatment with Schizophrenia.

BACKGROUND: Schizophrenia is a devastating mental disease that affects approximately 1% of the world's population. Breast cancer is the second most common type of cancer in the world that causes death in women. It is often unclear whether patients with schizophrenia receive recommended cancer treatment that met the guideline. This study characterized breast cancer treatment disruptions in schizophrenia patients and sought to identify and resolve correctable predictors of those disruptions. MATERIALS AND METHODS: A retrospective cohort study was conducted on 55 primary breast cancer patients diagnosed with schizophrenia and treated for breast cancer. We evaluated the characteristics of the breast cancer patients with schizophrenia compared to those of 610 breast cancer patients without schizophrenia. RESULTS: Compared to the control group, the schizophrenia group had significantly advanced T and N factors and disease stage. Significantly fewer patients in the schizophrenia group than in the control group received chemotherapy (P < .0001) or recommended cancer treatment (P = .0004). Within the schizophrenia group, the patients in need of ADL support were significantly less likely to receive recommended cancer treatment. CONCLUSION: Patients with schizophrenia are often diagnosed with breast cancer in advanced stages. In addition, patients with schizophrenia with reduced ADL are less likely to receive chemotherapy or recommended cancer treatment. It is highly recommended that patients with schizophrenia undergo breast cancer screening so that they can be diagnosed early and treated adequately.

Neoantigens elicit T cell responses in breast cancer.

Neoantigens are tumour-specific antigens that arise from non-synonymous mutations in tumour cells. However, their effect on immune responses in the tumour microenvironment remains unclear in breast cancer. We performed whole exome and RNA sequencing of 31 fresh breast cancer tissues and neoantigen prediction from non-synonymous single nucleotide variants (nsSNVs) among exonic mutations. Neoantigen profiles were determined by predictive HLA binding affinity (IC50 < 500 nM) and mRNA expression with a read count of ≥ 1. We evaluated the association between neoantigen load and expression levels of immune-related genes. Moreover, using primary tumour cells established from pleural fluid of a breast cancer patient with carcinomatous pleurisy, we induced cytotoxic T lymphocytes (CTLs) by coculturing neoantigen peptide-pulsed dendritic cells (DCs) with autologous peripheral lymphocytes. The functions of CTLs were examined by cytotoxicity and IFN-γ ELISpot assays. Neoantigen load ranged from 6 to 440 (mean, 95) and was positively correlated to the total number of nsSNVs. Although no associations between neoantigen load and mRNA expression of T cell markers were observed, the coculture of neoantigen-pulsed DCs and lymphocytes successfully induced CTLs ex vivo. These results suggest that neoantigen analysis may have utility in developing strategies to elicit T cell responses.

Effect of the 2013 ASCO-CAP HER2 Testing Guideline on the Management of IHC/HER2 2+ Invasive Breast Cancer.

BACKGROUND/AIM: With advances in anti-HER2 treatment and improved prognoses of HER2-positive breast cancer, the American Society of Clinical Oncology and the American Society of Pathologists (ASCO/CAP) have revised the HER2 diagnostic guidelines several times. We examined how to respond clinically to the revisions of the interpretation of the immunohistochemistry (IHC) method. PATIENTS AND METHODS: We re-evaluated 254 patients diagnosed as HER2 IHC equivocal, who underwent fluorescence in situ hybridization (FISH) before and after the IHC diagnostic criteria update in 2013. RESULTS: Twenty of 131 (15.3%) IHC equivocal cases by the ASCO/CAP 2007 guideline were IHC score 3+ and one of 20 (0.76%) was negative for FISH. Five of 123 (4.1%) IHC equivocal cases by the ASCO/CAP 2013 guideline were negative for IHC as per the 2007 guideline and four were positive for FISH. CONCLUSION: After revision of the ASCO/CAP 2013 guideline, 3.3% of HER2-negative cases before the revision should have received anti-HER2 treatment.

Validity of the prognostication tool PREDICT version 2.2 in Japanese breast cancer patients.

INTRODUCTION: PREDICT is a prognostication tool that calculates the potential benefit of various postsurgical treatments on the overall survival (OS) of patients with nonmetastatic invasive breast cancer. Once patient, tumor, and treatment details have been entered, the tool will show the estimated 5-, 10-, and 15-year OS outcomes, both with and without adjuvant therapies. This study aimed to conduct an external validation of the prognostication tool PREDICT version 2.2 by evaluating its predictive accuracy of the 5- and 10-year OS outcomes among female patients with nonmetastatic invasive breast cancer in Japan. METHODS: All female patients diagnosed from 2001 to 2013 with unilateral, nonmetastatic, invasive breast cancer and had undergone surgical treatment at Kyushu University Hospital, Fukuoka, Japan, were selected. Observed and predicted 5- and 10-year OS rates were analyzed for the validation population and the subgroups. Calibration and discriminatory accuracy were assessed using Chi-squared goodness-of-fit test and area under the receiver operating characteristic curve (AUC). RESULTS: A total of 636 eligible cases were selected from 1, 213 records. Predicted and observed OS differed by 0.9% (p = 0.322) for 5-year OS, and 2.4% (p = 0.086) for 10-year OS. Discriminatory accuracy results for 5-year (AUC = 0.707) and 10-year (AUC = 0.707) OS were fairly well. CONCLUSION: PREDICT tool accurately estimated the 5- and 10-year OS in the overall Japanese study population. However, caution should be used for interpretation of the 5-year OS outcomes in patients that are ≥65 years old, and also for the 10-year OS outcomes in patients that are ≥65 years old, those with histologic grade 3 and Luminal A tumors, and in those considering ETx or no systemic treatment.

Surgical treatment for breast cancer in a patient with erythropoietic protoporphyria and photosensitivity: a case report.

BACKGROUND: Erythropoietic protoporphyria (EPP) is a rare disorder of heme synthesis. Patients with EPP mainly show symptoms of photosensitivity, but approximately 20% of EPPs are associated with the liver-related complications. We report a case of breast cancer in a 48-year-old female patient with EPP in whom meticulous perioperative management was required in order to avoid complications resulting from this disease. CASE PRESENTATION: The patient was diagnosed with EPP at the age of 33 and had a rich family history of the disease. For right breast cancer initially considered as TisN0M0 (Stage 0), the right mastectomy and sentinel lymph node biopsy were performed, while the final stage was pT1bN0M0, pStage I. In the perioperative period, we limited the drug use and monitored light wavelength measurements. Besides, we covered surgical lights, headlights, and laryngoscope's light with a special polyimide film that filtered the wavelength of light causing dermal photosensitivity. After the surgery, any emerging complications were closely monitored. CONCLUSIONS: The surgery, internal medicine, anesthesiology, and operation departments undertook all possible measures through close cooperation to ensure a safe surgery for the patient with a rare condition.

Comprehensive molecular profiling broadens treatment options for breast cancer patients.

Precision oncology with next generation sequencing (NGS) using tumor tissue with or without blood has begun in Japan. Tumor molecular profiling tests are available, including the OncoGuide™ NCC Oncopanel System and FoundationOne® CDx (F1CDx). Our purpose was to identify potentially actionable genetic alterations in breast cancer with this comprehensive tumor profiling test. We enrolled 115 patients with pathologically diagnosed advanced or metastatic breast cancer. Comprehensive tumor genomic profiling, microsatellite instability, and tumor mutational burden (TMB) were determined using F1CDx. Testing was successful in 109/115 cases (94.8%). Clinically actionable alterations were identified in 76% of advanced breast cancer patients. The most frequent short variants were in TP53 (48.6%), PIK3CA (38.5%), GATA3 (11.0%), PTEN (11.0%), and BRCA1 (10.1%), and structural variants were in ERBB2 (24.8%), MYC (21.1%), RAD21 (21.1%), CCND1 (11.9%), FGF19 (10.1%), and PTEN (10.1%). Regarding human epidermal growth factor receptor (HER)2 status, 106/109 samples (97.2%) were concordant between F1CDx and HER2 testing with immunohistochemistry/fluorescence in situ hybridization. However, ERBB2 amplification was newly detected in four samples and ERBB2 mutations were detected in five HER2-negative breast cancer samples. Oncogenic BRCA mutations were found in three samples with F1CDx among 27 germline testing-negative samples. The mean TMB in all samples was 6.28 mut/Mb and tended to be higher in luminal B and triple-negative breast cancer (mean = 8.1 and 5.9 mut/Mb, respectively) compared with other subtypes. In conclusion, we established a system for precision oncology and obtained preliminary data with NGS as the first step. The information in this clinical sequencing panel will help guide the development of new treatments for breast cancer patients.

Breast metastasis from pelvic high-grade serous adenocarcinoma: a report of two cases.

BACKGROUND: Metastatic tumors to the breast reportedly account for 0.5% to 2.0% of all malignant breast diseases. Such metastatic tumors must be differentiated from primary breast cancer. Additionally, few reports have described metastases of gynecological cancers to the breast. We herein report two cases of metastasis of pelvic high-grade serous adenocarcinoma to the breast. CASE PRESENTATION: The first patient was a 57-year-old woman with a transverse colon obstruction. Colostomy was performed, but the cause of the obstruction was unknown. We found scattered white nodules disseminated throughout the abdominal cavity and intestinal surface. Follow-up contrast-enhanced computed tomography (CT) showed an enhanced nodule outside the right mammary gland. Core needle biopsy (CNB) of the right breast mass was conducted, and immunohistochemical staining of the mass suggested a high-grade serous carcinoma of female genital tract origin. We diagnosed the patient's condition as breast and lymph node metastasis of a high-grade serous carcinoma of the female genital tract. After chemotherapy for stage IVB peritoneal cancer, tumor reduction surgery was performed. The second patient was a 71-year-old woman with a medical history of low anterior resection for rectal cancer at age 49, partial right thyroidectomy for follicular thyroid cancer at age 53, and left lower lung metastasis at age 57. Periodic follow-up CT showed peritoneal dissemination, cancerous peritonitis, and pericardial effusion, and the patient was considered to have a cancer of unknown primary origin. Contrast-enhanced CT showed an enhanced nodule in the left mammary gland with many enhanced nodules and peritoneal thickening in the abdominal cavity. CNB of the left breast mass was conducted, and immunohistochemical staining of the mass suggested a high-grade serous carcinoma of female genital tract origin. After chemotherapy for stage IVB peritoneal cancer, tumor reduction surgery was performed. CONCLUSIONS: We experienced two rare cases of intramammary metastasis of high-grade serous carcinoma of female genital tract origin. CNB was useful for confirming the histological diagnosis of these cancers that had originated from other organs. A correct diagnosis of such breast tumors is important to ensure quick and appropriate treatment.

Microsatellite instability in Japanese female patients with triple-negative breast cancer.

BACKGROUND: It is important to identify biomarkers for triple-negative breast cancers (TNBCs). Recently, pembrolizumab, an immune checkpoint inhibitor (ICI) for programmed cell death 1 (PD-1), was approved as a treatment strategy for unresectable or metastatic tumor with high-frequency microsatellite instability (MSI-H) or mismatch repair deficiency, such as malignant melanoma, non-small cell lung cancer, renal cell cancer and urothelial cancer. In addition, results from clinical trials suggested that ICI was a promising treatment for TNBCs with accumulated mutations. However, the frequency of MSI in Japanese TNBCs still remains unclear. We aimed to analyze the presence of MSI-H in TNBCs as a biomarker for ICI therapy. METHODS: In this study, we retrospectively evaluated the MSI of 228 TNBCs using an innovative method, MSI Analysis System Version 1.2 (Promega), consisting of 5 microsatellite markers: BAT-26, NR-21, BAT-25, MONO-27 and NR-24 without a normal tissue control. RESULTS: Among 228 tumors, 222 (97.4%) were microsatellite stable, 4 (1.7%) low-frequency MSI and 2 (0.9%) MSI-H, respectively. Two MSI-H tumors were potentially aggressive pathologically as indicated by nuclear grade 3 and high Ki-67 (> 30%), and were classified as basal-like and non-BRCA-like, but were not consistent regarding tumor-infiltrating lymphocytes, CD8 and PD-L1 expression. CONCLUSIONS: Although we found that MSI-H was uncommon (0.9%) in TNBCs, potential targets for ICIs exist in TNBCs. Therefore, MSI-H breast cancer patients should be picked up using not only conventional methods but also platforms for comprehensive genomic profiling.

T-bet+ lymphocytes infiltration as an independent better prognostic indicator for triple-negative breast cancer.

PURPOSE: T-box transcription factor 21 (T-bet), which is the master regulator of effector T-cell activation, is derived by stimulation of T-cell receptors. In this study, we focused on T-bet and examined the function of activated T cells. METHODS: This study included 242 patients with primary triple-negative breast cancer (TNBC) who underwent resection without neoadjuvant chemotherapy between January 2004 and December 2014. The immunohistochemistry scoring for CD8 and T-bet expression on tumor-infiltrating lymphocytes (TILs) was defined as ≥ 30 per 6.25 × 10-3 mm2. RESULTS: Of the 242 TNBC cases, CD8 was positively expressed in 127 (52.5%) tumors, and T-bet was positively expressed in 67 (27.7%) tumors. T-bet expression was significantly correlated with CD8 expression (p < 0.0001). Patients with T-bet+ tumors had longer overall survival (OS) compared with patients with T-bet- tumors (p = 0.047). The combination of CD8+ and T-bet+ was associated with a better recurrence-free survival (RFS) and OS compared to CD8+/T-bet- tumors (p = 0.037 and p = 0.024, respectively). Adjuvant chemotherapy provided significantly greater benefit to patients with T-bet+ tumors (p = 0.031 for RFS, p = 0.0003 for OS). Multivariate analysis revealed that T-bet expression on TILs was an independent and positive prognostic indicator (HR = 0.36, 95% confidence interval (CI) 0.12-0.94, p = 0.037 for RFS, HR = 0.30, 95% CI 0.07-0.95, p = 0.039 for OS). CONCLUSIONS: OS was significantly improved for patients with high T-bet-expressing TILs in TNBC. Thus, T-bet may be a predictive indicator for survival and various immunotherapy strategies in TNBC.

QOL-enhancing surgery for patients with HER2-positive metastatic breast cancer.

The role of the resection of primary tumour in stage IV breast cancer is unclear. Systemic therapy is recommended to prolong the survival and improve the quality of life (QOL). However, even if the systemic therapy is effective to control distant metastasis, sometimes the local lesion worsens, especially in the aggressive subtypes such as HER2-positive breast cancer. In uncontrollable tumours, the wound bed can bleed, weep and get infected, leading to dismal QOL. Our study describes two cases of patients with HER2-positive stage IV breast cancer who underwent palliative mastectomy which resulted in improvement of QOL. Local tumour control through palliative mastectomy can be beneficial for symptomatic aggressive patients with HER2-positive breast cancer to improve their QOL.

[Significance of Endocrine Therapy for Unresected Primary Breast Cancer].

At present, surgery is still the recommended principal treatment for breast cancer. However, there are conditions in which surgery is not suitable, for example in elderly or high-risk patients and those who do not wish to undergo the procedure. This study presents a case series of 8 patients with unresected breast cancer who were administered hormonal therapy as an optional treatment. Patients included in the study were diagnosed with Stage I-III breast cancer from 2012 to 2015 at our institution. The patients were administered hormonal therapy for an average duration of 20.1 months. Complete responses were seen in 4 patients, while 1 and 3 patients were noted to have a partial response and stable disease, respectively. No disease progression was seen in any patients during the study period. Endocrine therapy may be an effective and safe option for patients with unresected breast cancer.

Visualizing Energy Charge in Breast Carcinoma Tissues by MALDI Mass-spectrometry Imaging Profiles of Low-molecular-weight Metabolites.

BACKGROUND/AIM: Metabolomics is widely used for biomarker discovery, but conventional mass-spectrometry extraction procedures lose the spatial localization of metabolites. In this study, we directly analyzed breast carcinoma tissues embedded in frozen tissue microarrays (fTMAs) using MALDI mass-spectrometry imaging (MALDI-MSI). MATERIALS AND METHODS: A total of 119 breast tissues (84 carcinoma and 35 normal) were used. MSI data were extracted from each tissue. RESULTS: Overall, 185 of 1,915 peaks which were commonly detected in 60% of target areas were subjected to further analysis. One hundred and fifty-two peaks of carcinoma showed significantly higher intensity than normal. Comparing metabolite profiles from carcinoma and normal tissues, energy charge (EC) and the sum of adenosine phosphate compound (AXP) indicated significantly higher intensities in cancerous tissues than normal. But comparisons of EC and AXP among lymph node metastasis, tumor size and tumor subtypes indicated no significant differences. CONCLUSION: Breast carcinoma tissues had higher EC and AXP values than normal. MALDI-MSI could be a tool for characterizing breast carcinoma.

Catumaxomab with Activated T-cells Efficiently Lyses Chemoresistant EpCAM-positive Triple-negative Breast Cancer Cell Lines.

BACKGROUND/AIM: Epithelial cell adhesion molecule (EpCAM) is expressed in various types of cancer, including breast cancer, and is correlated with metastasis, invasion, therapeutic resistance and prognosis. Moreover, several cell surface markers, such as CD44 and EpCAM, are molecular targets on cancer stem-like cells of breast cancer. The aim of this study was to investigate whether catumaxomab, a clinical-grade bispecific antibody that binds to both EpCAM on tumor cells and CD3 on T-cells, combined with activated T-cells can eliminate chemoresistant triple-negative breast cancer (TNBC) cells in vitro. MATERIALS AND METHODS: First, a cell line (MUK-BC1) was established from human breast carcinoma cells derived from a patient with chemoresistant and disseminated breast cancer. These EpCAM-positive TNBC cells were almost completely resistant to various drug-mediated cytotoxicities up to a concentration of 10 µg/ml. RESULTS: Pre-treatment with catumaxomab and subsequent addition of interleukin-2/OKT3-activated autologous T-cells eliminated EpCAM-positive TNBC cells. CONCLUSION: Catumaxomab combined with activated T-cells may be a potent therapeutic modality to overcome chemoresistant EpCAM-positive TNBC cells.

Efficacy and Safety of Bi-weekly Pegfilgrastim for Dose-dense Chemotherapy-induced Neutropenia in Breast Cancer Patients.

BACKGROUND/AIM: The dose-dense doxorubicin and cyclophosphamide (ddAC) for patients with HER-2-negative breast cancer is recommended by the National Comprehensive Cancer Network guideline in US. However, there are little data on serum G-CSF concentrations in patients undergoing bi-weekly dose-dense therapy with pegfilgrastim. The objective of this study was to compare the serum G-CSF concentrations in patients receiving pegfilgrastim in bi- or tri-weekly regimens. PATIENTS AND METHODS: This study included 26 patients who received ddAC or docetaxel and cyclophosphamide (TC) for primary breast cancer. Serum G-CSF concentrations were measured by ELISA. RESULTS: Serum G-CSF concentrations peaked in the second week of ddAC cases and in the ninth week of TC cases. Neutrophils gradually increased until the sixth week in ddAC cases, while they were slightly decreased during the first three weeks in TC cases. Treatments were completed without febrile neutropenia or treatment delays. CONCLUSION: Primary prophylactic pegfilgrastim administrations increased serum G-CSF concentrations, helping to maintain the absolute neutrophil counts that are required to undergo chemotherapy. The treatment of ddAC with 3.6 mg pegfilgrastim is completely safe for female Japanese patients.