記述言語：英語   掲載種別：研究論文（学術雑誌）  

Trastuzumab-emtansine (T-DM1) is a therapeutic agent molecularly targeting human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC), and it is especially effective for MBC with resistance to trastuzumab. Although several reports have described T-DM1 resistance, few have examined the mechanism underlying T-DM1 resistance after the development of acquired resistance to trastuzumab. We previously reported that YES1, a member of the Src family, plays an important role in acquired resistance to trastuzumab in HER2-amplified breast cancer cells. We newly established a trastuzumab/T-DM1-dual-resistant cell line and analyzed the resistance mechanisms in this cell line. At first, the T-DM1 effectively inhibited the YES1-amplified trastuzumab-resistant cell line, but resistance to T-DM1 gradually developed. YES1 amplification was further enhanced after acquired resistance to T-DM1 became apparent, and the knockdown of the YES1 or the administration of the Src inhibitor dasatinib restored sensitivity to T-DM1. Our results indicate that YES1 is also strongly associated with T-DM1 resistance after the development of acquired resistance to trastuzumab, and the continuous inhibition of YES1 is important for overcoming resistance to T-DM1.

DOI： 10.3390/ijms222312809

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Recent genome-wide association studies have shown that many single-nucleotide polymorphisms (SNPs) are associated with breast cancer risk. However, it is often unclear how these SNPs are related to breast cancer. Analysis of associations between SNPs and phenotypes may be important for determining mechanisms of action, including carcinogenesis. METHODS: In previous case-control studies, we found three SNPs (rs2046210, rs3757318, and rs3573318) associated with breast cancer risk in Japanese women. Among these SNPs, two (rs2046210 and rs3757318) are located at 6q25.1, in proximity to the estrogen receptor 1 gene (ESR1). Using data from these studies, we examined associations between factors related to breast cancer risk, such as height, weight, and breast density, and the three SNPs in cases and controls. We also investigated whether the SNPs correlated with breast cancer features, such as estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor type-2 (HER2) status, and clinical stage. RESULTS: There was a significant difference in mean height between risk and non-risk allele carriers for rs2046210 (156.0 ± 5.8 vs. 154.3 ± 5.5 cm, p = 0.002), and rs3757318 (155.8 ± 5.7 vs. 154.7 ± 5.6 cm, p = 0.035) in cases, but no significant associations between height and these SNPs in controls. There was also a significant difference in breast density between risk and non-risk allele carriers for rs2046210 (p = 0.040) and rs3757318 (p = 0.044) in cases. rs2046210 and rs3757318 risk allele carriers tended to have higher breast density in all subjects and in controls. In cases, rs3757318 risk allele carriers were also significantly more likely to be ER-negative compared to non-risk allele carriers (ER-positive rate: 77% vs. 84%, p = 0.036). CONCLUSIONS: SNPs rs2046210 and rs3757318, which are associated with breast cancer risk in Japanese women, were significantly associated with height and high breast density, and this association was particularly strong in those with breast cancer. These findings suggest that SNPs in the ESR1 gene region affect phenotypes such as height and breast density.

DOI： 10.1007/s12282-020-01185-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Epidemiological studies have suggested that intake of soy isoflavones is associated with a reduced risk of development of breast cancer and an improved prognosis in patients with breast cancer. In addition, basic research has demonstrated the antitumor effects of these compounds on breast cancer cell lines. However, the detailed effects of the intake of equol, which is one of the metabolites of the soy isoflavones, are yet to be clarified on the risk of development and recurrence of breast cancer and its interactions with drugs used for treating breast cancer. This study aimed to determine the antitumor effects of equol and investigate the impact of adding equol to therapeutic agents for breast cancer using breast cancer cell lines. METHODS: We examined the antitumor effect of equol on breast cancer cell lines using MTS assay. We also studied the combined effect of equol and the existing hormonal or chemotherapeutic agents using combination index. We evaluated the expressions of the related proteins by Western blot analysis and correlated the findings with the antitumor effect. RESULTS: Equol showed bi-phasic protumor and antitumor effects; at a low concentration, it promoted the tumor growth in hormone receptor-positive cell lines, whereas antitumor effects were generally observed when an excessive amount of dose unexpected in the blood and the tissue was administered. When used with tamoxifen, equol might have some antagonistic effect, although it depends on equol concentration and the type of cancer cells. CONCLUSIONS: We confirmed that equol has dual action, specifically a tumor growth-promoting effect and an antitumor effect. Although the results suggested that equol might exert an antagonistic effect against tamoxifen depending on the concentration, equol did not exert an antagonistic effect on other therapeutic agents.

DOI： 10.1007/s10549-020-05957-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Differentiated thyroid carcinoma (DTC) in juvenile patients is often an extensive and aggressive disease with a high frequency of recurrence. However, the prognosis is excellent, with a low mortality rate even when advanced disease is present, although prognostic factors and treatment strategy remain uncertain. Between April 2004 and March 2017, 33 juvenile patients (< 30 years old) were diagnosed with DTC and treated at our institution. We retrospectively investigated prognosis and factors including sex, reason for discovery, treatment, pathological factors and treatment progress to clarify the risk factors. All patients underwent curative surgical treatment. Pathologically, lymph node metastasis was identified in 25 patients (75%). Thirteen patients (39%) had bilateral cervical metastasis. In addition, 9 (27%) had more than 10 metastatic lymph nodes. The 2 patients with more than 20 metastatic lymph nodes were treated with radioactive iodine (RAI). Five patients (15%) had local recurrences and received surgery. There have been no further recurrences or deaths. However, no factors were determined to significantly predict the recurrence of juvenile DTC. Local recurrent disease was treated with surgery and/or RAI until remission, and survival was excellent in juvenile DTC.

DOI： 10.18926/AMO/60799

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Metastatic breast cancer (MBC), including de novo stage IV, is regarded as being incurable and the mainstay of clinical management is systemic therapy. Traditionally, locoregional surgery is performed only for local control, such as to prevent ulceration and bleeding. In recent years, however, both retrospective and prospective studies have demonstrated the prognostic efficacy of primary surgery for de novo stage IV patients. Therefore, we conducted a meta-analysis to evaluate whether surgical therapy contributes to overall survival (OS) extension. We searched for clinical trials published in electronic databases (PubMed, Embase, and the Cochrane databases) and performed a meta-analysis of the data collected. There were five prospective randomized controlled phase III trials (RCTs). The results of three have been reported. According to our meta-analysis of these RCTs, primary surgery for de novo stage IV breast cancer patients significantly improves OS. However, the Tata trial showed that systemic therapy does not achieve a sufficient effect. Another trial, conducted in Turkey, had statistical shortcomings and patient randomization was not adequately performed The ABCSG (Austrian Breast and Colorectal Cancer Study Group) trial had too few subjects. Meta-analysis of 12 retrospective studies showed that patients with stage IV breast cancer receiving surgery as the initial treatment experienced longer OS (HR: 0.65, P<0.00001). Based on our meta-analysis of three reported RCTs, surgery as the primary treatment does not significantly impact the outcomes of de novo stage IV breast cancer patients. However, these trials had limitations. We await the results of the remaining two ongoing RCTs (ECOG 2108 and JCOG 1017). These trials are anticipated to resolve current controversies and provide many eagerly awaited answers.

DOI： 10.21037/tcr.2020.01.60

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Metformin has been suggested to possibly reduce cancer risk. However, the mechanism underlying the positive effects of metformin on cancer treatment remains unclear. We conducted a prospective study to evaluate the effects of preoperative metformin in patients with early breast cancer. METHOD: We evaluated the effects on immunological factors (TILs, CD4 + , CD8 + , PD-L1, IFNγ and IL-2) by comparing core needle biopsies (CNB) obtained before metformin treatment with surgical specimens. Seventeen patients were enrolled in this prospective study from January to December 2016. We also analyzed 59 patients undergoing surgery during the same period to reveal the correlation of immune factors between CNB and surgical specimen. RESULT: There was a moderate correlation between CNB and surgical specimens on TILs and CD8 + lymphocyte. (TILs Rs = 0.63, CD4 + Rs = 0.224, CD8 + Rs = 0.42) In the metformin group, TILs increases were confirmed in five (29%) patients, while a decrease was confirmed in two (12%). The expressions of CD4 + and CD8 + by TILs were increased in 41% and 18% of surgical specimens, respectively. However, TILs number (p = 0.0554), CD4+ (p = 0.0613) and CD8 + (p = 0.0646) expressions did not significantly increased. Furthermore, IFNγ expression appeared to be increased in response to metformin (p = 0.08). CONCLUSION: Preoperative metformin tends to increase TILs, as well as the numbers of CD4 and CD8 positive lymphocytes, and IFNγ levels. Metformin might improve immune function and have a possibility of chemo-sensitivity and thereby increase the effectiveness of immunotherapy, based on the results of this preliminary study.

DOI： 10.1007/s00280-020-04092-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

INTRODUCTION: Patients with residual disease usually have a poor prognosis after neoadjuvant chemotherapy for breast cancer. The aim of this study was to explore therapeutic targets and potential additional adjuvant treatments for patients with residual disease after standard neoadjuvant chemotherapy. PATIENTS AND METHODS: We retrieved publicly available complementary DNA microarray data from 399 human epidermal growth factor receptor 2 (HER2)-negative primary breast cancer samples from patients who underwent standard neoadjuvant chemotherapy. We analyzed the messenger RNA (mRNA) expression levels of key breast cancer markers and therapeutic target genes according to residual cancer burden (RCB) classification: RCB-0/I, RCB-II, and RCB-III. RESULTS: Among hormone receptor-positive samples, there were more luminal A tumors by PAM50 (Prediction Analysis of Microarray 50 [Prosigna], aka Prosigna Breast Cancer Prognostic Gene Signature Assay) in RCB-III than in RCB-0/I and RCB-II (P < .01). The mRNA expressions of ESR1 and PGR were significantly higher, and that of MKI67 was lower in RCB-II and RCB-III than in RCB-0/I. The mRNA expression of cyclin D1 was up-regulated in RCB-III and that of CDKN2A was down-regulated in RCB-III (P = .027 and < .01). Among triple-negative (TN) samples, RCB-III had higher clinical stage and more lymph node-positive samples than RCB-0/1 and RCB-II (P < .01). In both subtypes, VEGF-C expression was significantly higher in RCB-III than in RCB-0/I and RCB-II. CONCLUSION: In hormone receptor-positive breast cancer, biological features such as luminal A were associated with RCB; this trend was not observed in TN breast cancer. Further, some targeted therapies should be tested as new strategies after standard neoadjuvant chemotherapy in future clinical trials.

DOI： 10.1016/j.clbc.2019.07.001

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記述言語：英語   出版者・発行元：AMER ASSOC CANCER RESEARCH  

DOI： 10.1158/1538-7445.SABCS19-P5-13-04

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Angiosarcoma of the breast is very rare and can be divided into primary and secondary angiosarcoma. Radiation-induced angiosarcoma (RIAS) is classified as secondary angiosarcoma. Diagnosis of RIAS is difficult due to its rarity, and the interpretation of pathological imaging is complicated. In the National Comprehensive Care Network (NCCN) guidelines, the first choice of treatment is surgery with negative margins. Adjuvant radiotherapy (RT) for close soft tissue margins should be considered. Preoperative or adjuvant chemotherapy of nonmetastatic disease is not recommended for angiosarcoma. We report a case of RIAS, which was impossible to diagnose with core needle biopsy (CNB) but was diagnosed by excisional biopsy. The patient was then administered adjuvant chemotherapy using conjugated paclitaxel (PTX). CASE PRESENTATION: A 62-year-old woman noticed a tumor in her right breast. She had a history of right breast cancer and had undergone breast-conserving surgery, RT, and tamoxifen therapy 8 years previously. CNB, which was performed twice, was inconclusive. The tumor was surgically excised and pathological analysis yielded a diagnosis of angiosarcoma. She then underwent a right mastectomy. One month after she underwent right mastectomy, a nodule reappeared on the skin of her right breast, and excisional biopsy revealed recurrence of angiosarcoma. A few weeks later another nodule reappeared near the post-operative scar and excisional biopsy revealed recurrence of angiosarcoma. We assumed that surgical therapy was insufficient because the patient experienced relapse of angiosarcoma after complete mastectomy. After the second recurrence, we treated her with systemic chemotherapy using PTX. There was no evidence of recurrence 8 months after chemotherapy. CONCLUSION: Although angiosarcoma is difficult to diagnose, many patients have a poor prognosis. Therefore, prompt treatment intervention is desired. Moreover, there is little evidence regarding adjuvant therapy of angiosarcoma since it is a rare disease. We consider that adjuvant therapy helped to effectively prevent recurrence in the patient after complete excision.

DOI： 10.1186/s40792-020-0790-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Adverse effects on fertility are a significant problem for premenopausal breast cancer patients. Since April 2009, we have been referring young patients for fertility counseling provided by a multidisciplinary team. Here we evaluated the efficacy and safety of our current fertility preservation approach. We retrospectively analyzed the cases of 277 patients < 45 years old at diagnosis, which was made between 2009 and 2016. Seventy-two (26%) patients received fertility counseling. Seventeen (6%) of the 277 patients decided to preserve their fertility before starting adjuvant systemic therapy. Six (35%) patients underwent oocyte cryopreservation, and 11 (65%) married patients opted for embryo cryopreservation. There were no pregnancies among the patients undergoing oocyte cryopreservation, whereas 3 (27%) of the patients who opted for embryo cryopreservation became pregnant. Two (12%) patients stopped endocrine therapy after 2 years in an effort to become pregnant, but their breast cancers recurred. Though the problem of fertility loss for breast cancer patients is important and we should assess the infertility risk for all patients, we should also consider the prognosis. In June 2016, we launched a prospective multicenter cohort study to evaluate the efficacy and safety of fertility preservation in greater detail.

DOI： 10.18926/AMO/55854

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

We managed 6 cases of severe liver atrophy and failure associated with paclitaxel and bevacizumab combination therapy (PB therapy)for HER2-negative metastatic breast cancer. In this case-controlstudy, we examined the records of these 6 patients to investigate past treatment, medication history, and degree of atrophy, and compared their data with that of 67 patients without liver atrophy. The degree of the liver atrophy used SYNAPSE VINCENT®of the image analysis software. The results showed that patients with liver atrophy had a longer pretreatment period than those without liver atrophy(33.5 months vs 15.5 months), and they also experienced a longer median time to treatment failure with PB therapy than other patients(11 months vs 6 months). The ratio of individuals presenting with diffuse liver metastasis among patients with liver metastasis was 80% with liver atrophy, compared to 8% without liver atrophy. The degree of liver atrophy was an average of 67%in terms of volume ratio before/after PB therapy(57-82%). The individualwith the greatest extent of liver atrophy died of liver failure, not as a result of breast cancer progression. The direct causal link between bevacizumab and liver atrophy and failure is unclear, but the individuals in this study had a long previous history of treatment, and diffuse liver metastases may develop in patients undergoing long periods of PB therapy, which may also cause liver atrophy; therefore, the possibility of liver failure should be considered in such cases.

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