Long-term outcomes of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1 + P) and docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) for HER2-positive primary breast cancer: results of the randomized phase 2 JBCRG20 study (Neo-peaks).

PURPOSE: The randomized phase 2 Neo-peaks study examined usefulness of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1 + P) following docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) as compared with the standard TCbHP regimen. We previously reported that pCR rate after neoadjuvant therapy tended to be higher with TCbHP followed by T-DM1 + P. We conducted an exploratory analysis of prognosis 5 years after surgery. METHODS: Neoadjuvant treatment with TCbHP (6 cycles; group A), TCbHP (4 cycles) followed by T-DM1 + P (4 cycles; group B), and T-DM1 + P (4 cycles; group C, + 2 cycles in responders) were compared. Group C non-responders after 4 cycles were switched to an anthracycline-based regimen. We evaluated 5-year disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS). RESULTS: Data from 203 patients (50, 52, and 101 in groups A-C, respectively) were analyzed. No significant intergroup differences were found for DFS, DDFS, or OS. The 5-year DFS rates (95% CI) were 91.8% (79.6-96.8%), 92.3% (80.8-97.0%), and 88.0% (79.9-93.0%) in groups A-C, respectively. TCbHP followed by T-DM1 + P and T-DM1 + P with response-guided addition of anthracycline therapy resulted in similar long-term prognosis to that of TCbHP. CONCLUSIONS: In patients who achieved pCR after neoadjuvant therapy with T-DM1 + P, omission of adjuvant anthracycline may be considered, whereas treatment should be adjusted for non-pCR patients with residual disease. T-DM1 + P with response-guided treatment adjustment may be useful for minimizing toxicity. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: UMIN-CTR, UMIN000014649, prospectively registered July 25, 2014. Some of the study results were presented as a Mini Oral session at the ESMO Breast Cancer 2023 (Berlin, Germany, 11-13 May 2023).

Time trend of breast cancer-related lymphedema according to body mass index.

PURPOSE: To clarify how body mass index (BMI) affects the development and temporal trend of breast cancer-related lymphedema (BCRL). METHODS: This is a prospective study in which patients with operable breast cancer were registered in a single institute between November 2009 and July 2010. The incidence of lymphedema at 1, 3, and 5 years after surgery was assessed according to BMI, and the trend of newly developed BCRL was examined. Obesity was defined as BMI ≥25 in accordance with the Japan Society for the Study of Obesity. RESULTS: A total of 368 patients were included in this study. The multivariate analysis of the whole population showed that high BMI, axillary dissection, and radiotherapy remained as risk factors for BCRL. Patients with high BMI showed a significantly higher incidence of new lymphedema than those with low BMI at 1 year (p < 00.001) regardless of axillary procedures (39.1 % vs 16.3 % for axillary dissection; 15.6 % vs 1.5 % for sentinel lymph node biopsy) but not at 3 and 5 years. Once BCRL developed, patients with high BMI showed slow recovery and 50.0 % of the patients retained edema at 5 years while patients with low BMI showed rapid recovery and 26.7 % retained after 3 years (p = 0.04). CONCLUSION: The preoperative BMI affected the incidence and temporal trend of BCRL regardless of axillary procedures or radiotherapy. Patients with high BMI should be given appropriate information about BCRL before surgery with careful follow-up for BCRL after treatment.

Analysis of the interaction between the ORF42 and ORF55 proteins encoded by Kaposi's sarcoma-associated herpesvirus.

Kaposi's sarcoma-associated herpesvirus (KSHV) causes Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. The tegument is a structure that is unique to herpesviruses that includes host and viral proteins, including the viral ORF42 and ORF55 proteins. Alphaherpesvirus tegument proteins have been well studied, but much is unknown regarding KSHV. Here, we report an interaction between the ORF42 and ORF55 proteins. ORF55 interacted with and recruited ORF42 from the nucleus to the cytoplasm. When ORF42 and ORF55 were expressed simultaneously in cultured cells, the expression level of these two viral proteins was higher than when either was expressed independently. ORF55, but not ORF42, was polyubiquitinated, suggesting that an unidentified regulatory mechanism may be present. A recombinant virus with an ectopic stop codon in ORF42 exhibited normal replication of genomic DNA, but fewer virus particles were released with the recombinant than with the wild-type virus. A unique R136Q mutation in ORF42, which is found in a KSHV strain that is prevalent on Miyako Island, Okinawa Prefecture, Japan, further increased the expression of ORF42 and ORF55 when these proteins were expressed simultaneously. However, the ORF42 R136Q mutation did not affect the localization pattern of ORF42 itself or of ORF55. In addition, experiments with a recombinant virus possessing the ORF42 R136Q mutation showed lower levels of production of the mutant virus than of the wild-type virus, despite similar levels of genome replication. We suggest that the R136Q mutation in ORF42 plays an important role in ORF55 protein expression and virus production.

Time-series blood cytokine profiles correlate with treatment responses in triple-negative breast cancer patients.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most heterogeneous breast cancer subtype. Partly due to its heterogeneity, it is currently challenging to stratify TNBC patients and predict treatment outcomes. METHODS: In this study, we examined blood cytokine profiles of TNBC patients throughout treatments (pre-treatment, during chemotherapy, pre-surgery, and 1 year after the surgery in a total of 294 samples). We analyzed the obtained cytokine datasets using weighted correlation network analyses, protein-protein interaction analyses, and logistic regression analyses. RESULTS: We identified five cytokines that correlate with good clinical outcomes: interleukin (IL)-1α, TNF-related apoptosis-inducing ligand (TRAIL), Stem Cell Factor (SCF), Chemokine ligand 5 (CCL5 also known as RANTES), and IL-16. The expression of these cytokines was decreased during chemotherapy and then restored after the treatment. Importantly, patients with good clinical outcomes had constitutively high expression of these cytokines during treatments. Protein-protein interaction analyses implicated that these five cytokines promote an immune response. Logistic regression analyses revealed that IL-1α and TRAIL expression levels at pre-treatment could predict treatment outcomes in our cohort. CONCLUSION: We concluded that time-series cytokine profiles in breast cancer patients may be useful for understanding immune cell activity during treatment and for predicting treatment outcomes, supporting precision medicine. TRIAL REGISTRATION: The study has been registered with the University Hospital Medical Information Network Clinical Trials Registry ( http://www.umin.ac.jp/ctr/index-j.htm ) with the unique trial number UMIN000023162. The association Japan Breast Cancer Research Group trial number is JBCRG-22. The clinical outcome of the JBCRG-22 study was published in Breast Cancer Research and Treatment on 25 March 2021. https://doi.org/10.1007/s10549-021-06184-w .

Influence of menopause on chemotherapy-induced nausea and vomiting in highly emetogenic chemotherapy for breast cancer: A retrospective observational study.

BACKGROUND: Female sex and younger age are reported risk factors for chemotherapy-induced nausea and vomiting (CINV) in highly emetogenic chemotherapy, but the underlying mechanism has not been elucidated. The purpose of this study was to clarify the impact of menopause on CINV. METHODS: This retrospective observational study analyzed data from consecutive patients who received their first cycle of perioperative anthracycline-based chemotherapy for breast cancer between January 2018 and June 2020. The endpoints were association between CINV (vomiting, ≥Grade 2 nausea, complete response [CR] failure) and menopause as well as the association between CINV and follicle-stimulating hormone [FSH]/estradiol [E2]. RESULTS: Data for 639 patients were analyzed. Among these patients, 109 (17.1%) received olanzapine (four antiemetic combinations) and 530 (82.9%) did not (three antiemetic combinations). Premenopausal state (amenorrhea lasting ≥12 months) was significantly associated with ≥Grade 2 nausea and CR failure in univariate analysis but not in multivariate analysis. The premenopausal FSH/E2 group (defined by serum levels; FSH <40 mIU/mL and E2 ≥20 pg/mL) had a significantly higher rate of ≥Grade 2 nausea than the postmenopausal FSH/E2 group (FSH ≥40 mIU/mL and E2 <20 pg/mL) (48.8% vs. 18.8%, p = 0.023). CONCLUSIONS: Our results suggest that changes in FSH and E2 due to menopause may affect the severity of nausea and that FSH and E2 (especially FSH) levels might be useful indicators for CINV risk assessment.

A risk-based subgroup analysis of the effect of adjuvant S-1 in estrogen receptor-positive, HER2-negative early breast cancer.

PURPOSE: The Phase III POTENT trial demonstrated the efficacy of adding S-1 to adjuvant endocrine therapy for estrogen receptor-positive, HER2-negative early breast cancer. We investigated the efficacy of S-1 across different recurrence risk subgroups. METHODS: This was a post-hoc exploratory analysis of the POTENT trial. Patients in the endocrine-therapy-only arm were divided into three groups based on composite risk values calculated from multiple prognostic factors. The effects of S-1 were estimated using the Cox model in each risk group. The treatment effects of S-1 in patients meeting the eligibility criteria of the monarchE trial were also estimated. RESULTS: A total of 1,897 patients were divided into three groups: group 1 (≤ lower quartile of the composite values) (N = 677), group 2 (interquartile range) (N = 767), and group 3 (> upper quartile) (N = 453). The addition of S-1 to endocrine therapy resulted in 49% (HR: 0.51, 95% CI: 0.33-0.78) and 29% (HR: 0.71, 95% CI 0.49-1.02) reductions in invasive disease-free survival (iDFS) events in groups 2 and 3, respectively. We could not identify any benefit from the addition of S-1 in group 1. The addition of S-1 showed an improvement in iDFS in patients with one to three positive nodes meeting the monarchE cohort 1 criteria (N = 290) (HR: 0.47, 95% CI: 0.29-0.74). CONCLUSIONS: The benefit of adding adjuvant S-1 was particularly marked in group 2. Further investigations are warranted to explore the optimal usage of adjuvant S-1.

Fulvestrant with or without anti-HER2 therapy in patients in a postmenopausal hormonal state and with ER-positive HER2-positive advanced or metastatic breast cancer: A subgroup analysis of data from the Safari study (JBCRG-C06).

BACKGROUND: The role of endocrine therapy in the treatment of patients in a postmenopausal hormonal state and with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer (AMBC) is unclear. METHODS: We analyzed the data from 94 patients with ER-positive HER2-positive AMBC enrolled in the Safari study (UMIN000015168), a retrospective cohort study of 1072 ER-positive AMBC patients in a postmenopausal hormonal state who received fulvestrant 500 mg (F500): (1) to compare time to treatment failure (TTF) and overall survival (OS) by treatment group, and TTF by treatment line; (2) in patients who received endocrine therapy (including F500) or anti-HER2 therapy as initial systemic therapy before chemotherapy, to investigate relations between TTF for the first-line therapy or time to chemotherapy (TTC) and OS; (3) to investigate factors associated with OS. RESULTS: The TTF was longer in the patients treated with F500 as first- or second-line therapy (n = 20) than in those who received later-line F500 therapy (n = 74) (6.6 vs. 3.7 months; HR, 1.98; p = 0.014). In the 59 patients who received endocrine therapy or anti-HER2 therapy as initial systemic therapy before chemotherapy, those with TTC ≥3 years had longer median OS than those with TTC <3 years (10.5 vs. 5.9 years; HR, 0.32; p = 0.001). Longer TTC was associated with prolonged OS. CONCLUSIONS: In patients with ER-positive HER2-positive AMBC enrolled in the Safari study, TTF was longer in patients who received F500 as first- or second-line therapy. In patients who received chemotherapy-free initial systemic therapy, the prolonged OS in those with TTC ≥3 years suggests that this value may be a helpful cut-off for indicating clinical outcomes.

Real-world data analysis of perioperative chemotherapy patterns, G-CSF use, and FN status in patients with early breast cancer.

PURPOSE: This study aimed to describe perioperative chemotherapy patterns, granulocyte colony-stimulating factor (G-CSF) use, and febrile neutropenia (FN) status in patients with early breast cancer (EBC) using real-world data in Japan. METHODS: This retrospective observational study used anonymized claims data. The included patients were ≥ 18 years old, were female, and had breast cancer diagnosis and surgery records between January 2010 and April 2020. Measures included perioperative chemotherapy, G-CSF use (daily and primary prophylaxis [PP]), and FN and FN-related hospitalization (FNH), all examined annually. Perioperative chemotherapy was examined separately for human epidermal growth factor receptor 2-positive/negative (HER2±). A multivariate logistic regression was used to explore the factors associated with FNH. RESULTS: Of 32,597 patients, those with HER2 + EBC treated with anthracycline-based regimens followed by taxane + trastuzumab + pertuzumab increased since 2018, and those with HER2 - EBC treated with doxorubicin/epirubicin + cyclophosphamide followed by taxane and dose-dense regimens increased after 2014. The proportion of patients prescribed daily G-CSF declined after 2014, whereas that of pegfilgrastim PP increased. The incidence proportion of FN remained at approximately 24-31% from 2010 to 2020, while that of FNH declined from 14.5 to 4.0%. The odds of FNH were higher in those aged ≥ 65 years and lower with pegfilgrastim PP administration. CONCLUSION: Despite the increasing use of escalated regimens in the last 5-6 years, FNH continuously declined, and the odds of FNH were lower among patients treated with pegfilgrastim PP. These results may suggest the contribution of PP in part to suppressing FNH levels over the last 5-6 years.

Chromatin conformational changes at human satellite II contribute to the senescence phenotype in the tumor microenvironment.

Cellular senescence and senescence-associated secretory phenotype (SASP) in stromal cells within the tumor microenvironment promote cancer progression. Although cellular senescence has been shown to induce changes in the higher-order chromatin structure and abnormal transcription of repetitive elements in the genome, the functional significance of these changes is unclear. In this study, we examined the human satellite II (hSATII) loci in the pericentromere to understand these changes and their functional significance. Our results indicated that the hSATII loci decompact during senescence induction, resulting in new DNA-DNA interactions in distinct genomic regions, which we refer to as DRISR (Distinctive Regions Interacted with Satellite II in Replicative senescent Fibroblasts). Interestingly, decompaction occurs before the expression of hSATII RNA. The DRISR with altered chromatin accessibility was enriched for motifs associated with cellular senescence and inflammatory SASP genes. Moreover, DNA-fluorescence in situ hybridization analysis of the breast cancer tissues revealed hSATII decompaction in cancer and stromal cells. Furthermore, we reanalyzed the single-cell assay for transposase-accessible chromatin with sequencing data and found increased SASP-related gene expression in fibroblasts exhibiting hSATII decompaction in breast cancer tissues. These findings suggest that changes in the higher-order chromatin structure of the pericentromeric repetitive sequences during cellular senescence might directly contribute to the cellular senescence phenotype and cancer progression via inflammatory gene expression.

Factors associated with financial toxicity in patients with breast cancer in Japan: a comparison of patient and physician perspectives.

BACKGROUND: Financial toxicity (FT) is a notable concern for patients with breast cancer worldwide. The situation regarding FT in Japan, however, has not been well explored. This study examined FT in patients with breast cancer in Japan and presented an overview of the group study's overall findings. METHODS: The survey used the Questant application and primarily targeted patients with breast cancer attending research facilities and physicians who are members of the Japanese Breast Cancer Society. The Japanese version of the Comprehensive Score for FT (COST) was used to quantify patients' FT. Multiple regression analysis was used to identify factors related to FT in patients with breast cancer in Japan and evaluate the sufficiency of information support level (ISL) for medical expenses. RESULTS: We collected 1558 responses from patients and 825 from physicians. In terms of factors affecting FT, recent payments had the highest impact, followed by stage, and related departments positively affecting FT. Conversely, factors such as income, age, and family support were found to negatively affect FT. A significant discrepancy was identified between patients and physicians in perceived information support, with patients frequently feeling unsupported and physicians believing that they have provided adequate support. Furthermore, differences in the frequency of explanations and opportunities to ask questions about medical costs across FT grades were found. The analysis also showed that physicians with a better understanding of information support needs and greater knowledge of medical costs tended to provide more support that is comprehensive. CONCLUSION: This study emphasizes the importance of addressing FT in patients with breast cancer in Japan and highlights the need for enhanced information support, deeper understanding by physicians, and collaborative efforts among professionals to mitigate financial burden and provide personalized, tailored support for individual needs.

Oncofertility-related psycho-educational therapy for young adult patients with breast cancer and their partners: Randomized controlled trial.

BACKGROUND: A couples' psycho-educational program called Oncofertility! Psycho-Education and Couple Enrichment (O!PEACE) therapy was created and its effect when provided before cancer treatment was examined. METHODS: This multicenter randomized controlled trial with nonmasking, parallel two-group comparison enrolled women aged 20 to 39 years with early-stage breast cancer and their partners. They were randomly assigned to receive O!PEACE (37 couples) or usual care (37 couples). Primary end points were cancer-related posttraumatic stress symptoms, symptoms of depression, and anxiety. Secondary end points were stress-coping strategies, resilience, and marital relationship. RESULTS: Women receiving psycho-educational therapy had significantly reduced Impact of Event Scale-revised version for Japanese scores (p = .011, ηp 2  =  = .089). For patients with Impact of Event Scale-revised version for Japanese scores at baseline ≥18.27, O!PEACE therapy improved these scores when compared with usual care (U = 172.80, p = .027, r = 0.258). A >5-point reduction was present in 59.3% and 30% of women in the O!PEACE therapy and usual-care groups, respectively. For partners, O!PEACE therapy significantly improved stress-coping strategies (95% CI, -0.60 to -0.05; p = .018, ηp 2  =  = .074) and escape-avoidance marital communication (95% CI, -0.33 to -0.08; p = .001, ηp 2  = .136). O!PEACE therapy significantly improved the partners' support (95% CI, 0.10-0.50; p = .001, ηp 2  = .127), the rate of receiving fertility preservation consultations, and knowledge levels. CONCLUSIONS: O!PEACE therapy before cancer treatment can improve posttraumatic stress symptoms, stress-coping behavior, and marital relationships. Larger sample sizes and longer term follow-up are required. PLAIN LANGUAGE SUMMARY: A psycho-educational program, the Oncofertility! Psycho-Education and Couple Enrichment (O!PEACE) therapy program was developed and evaluated for women diagnosed with breast cancer and their partners. A multicenter randomized controlled trial showed that the O!PEACE psycho-educational therapy, with only two precancer treatment sessions, can reduce cancer-related posttraumatic stress symptoms and improve oncofertility knowledge and marital relationships in young adult patients with breast cancer. The therapy could also improve stress-coping strategies in marital communications with their partners. Couples may use O!PEACE psycho-educational therapy to consider fertility preservation and improve their psychosocial aspects.

Conserved cysteine residues in Kaposi's sarcoma herpesvirus ORF34 are necessary for viral production and viral pre-initiation complex formation.

Kaposi's sarcoma herpesvirus (KSHV) ORF34 is a component of the viral pre-initiation complex (vPIC), a highly conserved piece of machinery essential for late gene expression among beta- and gamma-herpes viruses. KSHV ORF34 is also estimated to be a hub protein, associated with the majority of vPIC components. However, the precise mechanisms underlying how the ORF34 molecule contributes to the vPIC function, including the binding manner to other vPIC components, remain unclear. Therefore, we constructed ORF34 alanine-scanning mutants, in which amino-acid residues that were conserved among other herpesviruses had been replaced by alanine. The mutants were analyzed for their binding functions to other vPIC factors, and then were evaluated for their recovering ability of viral production using the cells harboring ORF34-deficient KSHV-BAC. The results demonstrated that at least four cysteines conserved in ORF34 were crucial for binding to other vPIC components, ORF24 and ORF66, virus production, and late gene transcription and expression. Based on the amino acid sequence of ORF34, these four cysteines were expected to constitute a pair of C-Xn-C consensus motifs. An artificial intelligence-predicted structure model revealed that the four cysteines were present tetrahedrally in an intramolecular fashion. Another prediction algorithm indicated the possible capture of metal cations by ORF34. Furthermore, it was experimentally observed that the elimination of cations by a selective chelator resulted in the loss of ORF34's binding ability to other vPIC components. In conclusion, our results suggest the functional importance of KSHV ORF34 conserved cysteines for vPIC components assembly and viral replication.

Intratumoral heterogeneity, treatment response, and survival outcome of ER-positive HER2-positive breast cancer.

BACKGROUND: ER+HER2+ breast cancer requires most types of systemic therapies perioperatively. However, treatment resistance is often experienced. The current study investigated the predictive and prognostic value of intratumoral heterogeneity and conventional clinicopathological factors in patients with ER+HER2+ breast cancer. METHODS: This research included two patient cohorts with ER+HER2+ breast cancer. Cohort A included patients who underwent surgery without neoadjuvant chemotherapy (NAC). Cohort B comprised patients who received NAC followed by surgery. Intratumoral heterogeneity was assessed via ER and HER2 double staining, and the number of cells stained with different patterns of ER and HER2 was counted. RESULTS: In total, 11 of 92 tumors in cohort A and four of 45 tumors in cohort B consisted exclusively of double-positive (ER+ and HER2+) cells (homogeneous). The rest had different combinations of cells (heterogeneous). The pathological complete response (pCR) rates differed based on tumoral cell components but not intratumoral heterogeneity. The pCR rate of tumors with ER-HER2+ cells but without HER2- cells was higher than that of others (45.5% vs 4.3%; p = 0.0013). Low ER and PgR Allred scores indicated better pCR rates than high scores (p = 0.0005 and 0.024, respectively). Multivariate analysis showed that the ER Allred score and cell component of ER-HER2+ cells without HER2- cells were independent predictors of pCR (p = 0.0055 and 0.0081, respectively). In cohort B, posttreatment Ki67, but not pCR, was a prognostic factor of DFS and OS (p = 0.028 and 0.017, respectively). The prognostic value of combined posttreatment Ki67 and pCR was superior to that of either alone. Combined pCR and posttreatment Ki67 had an independent prognostic value for DFS and OS (p = 0.0068 and 0.0101, respectively). CONCLUSIONS: In ER+HER2+ breast cancer, the presence of ER-HER2+ cells without HER2- cells was independently associated with pCR. Combined posttreatment Ki67 and pCR can be more precise in predicting prognosis than pCR alone.

Childbirth after perioperative systemic therapy in patients with breast cancer: a retrospective single institutional study in Japan.

BACKGROUND: The number of breast cancer patients of childbearing age has been increasing. Therefore, we investigated the characteristics and the childbearing status of the patients who received systemic therapy for breast cancer during their childbearing age to better understand the clinical impact of childbirth. METHODS: Female patients with breast cancer younger than 40 years old who underwent surgery and received perioperative systemic therapy from 2007 to 2014 were included in this study. We compared the characteristics of patients with and without childbirth after treatment. RESULT: Of 590 patients, 26 delivered a child, and 355 did not bear a child during the median observation period of 8.1 years, whilst 209 had unknown childbirth data. The childbirth group had a lower mean age at surgery (32.2 vs. 35.1, P < 0.001). The proportion of patients who desired childbirth and used assisted reproductive technology was significantly higher in the childbirth group (65.4 vs. 23.9% and 45.2 vs. 5.1%, respectively, P < 0.001). The patients in the childbirth group had significantly less advanced disease (P = 0.002). In the childbirth group, the age at childbirth was significantly older in patients who received combined endocrine therapy and chemotherapy (40.8 years) than in patients who received either alone (endocrine therapy: 36.9 years, chemotherapy: 36.7 years, P = 0.04). However, survival was not different between those with and without childbirth. CONCLUSION: It is critical to recognize the desire for childbirth in patients with breast cancer who are receiving systemic therapy and to provide them with necessary fertility information before treatment to support their decision-making.

Chromatin profile-based identification of a novel ER-positive breast cancer subgroup with reduced ER-responsive element accessibility.

BACKGROUND: Oestrogen receptor (ER) signalling-dependent cancer cell growth is one of the major features of ER-positive breast cancer (BC). Inhibition of ER function is a standard and effective treatment for ER-positive tumours; however, ~20% of patients with ER-positive BC experience early or late recurrence. In this study, we examined intertumour heterogeneity from an epigenetic perspective based on the hypothesis that the intrinsic difference in epigenetic states around ER signalling pathway underlies endocrine therapy resistance. METHODS: We performed transposase-accessible chromatin sequencing (ATAC-seq) analysis of 42 BC samples, including 35 ER-positive(+) human epidermal growth factor receptor 2 (HER2)-negative(-) and 7 triple-negative tumours. We also reanalysed ATAC-seq data of 45 ER + /HER2 - tumours in the Cancer Genome Atlas (TCGA) BC cohort to validate our observations. RESULTS: We conducted a comprehensive analysis of cis-regulatory elements (CREs) using ATAC-seq, identifying three subgroups based on chromatin accessibility profiles. We identified a subgroup of ER-positive BCs with a distinctive chromatin accessibility pattern including reduced accessibility to ER-responsive elements (EREs). The same subgroup was also observed in TCGA BC cohort. Despite the reduced accessibility to EREs, the expression of ER and potential ER target genes were not decreased in these tumours. CONCLUSION: Our findings highlight the existence of a subset of ER-positive BCs with unchanged ER expression but reduced EREs accessibility that cannot be distinguished by conventional immunostaining for ER. Future studies should determine whether these tumours are associated with resistance to endocrine therapy.

The impact of obesity and endocrine therapy on the prognosis of premenopausal women with hormone receptor-positive breast cancer: A single-institute retrospective study.

BACKGROUND: Higher body mass index (BMI) is associated with worse prognosis in pre- and postmenopausal patients with breast cancer (BC). However, there is insufficient evidence regarding the optimal adjuvant endocrine therapy for obese premenopausal women with hormone receptor (HR)-positive BC. AIM: To evaluate the impact of obesity and adjuvant endocrine therapy on prognosis in premenopausal patients with BC. METHODS AND RESULTS: We retrospectively reviewed the medical record of premenopausal women who received curative surgery for clinical stage I-III HR-positive BC from 2007 to 2017. Patients were classified into five groups according to BMI: underweight (UW), normal weight (NW), obese 1 degree (OB1), obese 2 degree (OB2), and obese 3 degree (OB3) categories. The primary analysis was a comparison of BC-specific survival (BCSS) according to BMI (UW/NW vs. OB1-3) and adjuvant endocrine therapy (with or without ovarian function suppression [OFS]). Of 13 021 patients, the data of 3380 patients were analyzed. BCSS in OB1-3 patients was significantly worse than that in patients with UW/NW (hazard ratio [HR] 2.37; 95% confidence interval [CI], 1.40-4.02: p = .0009). In OB1-3 patients who received tamoxifen (TAM), BCSS was significantly worse than that in UW/NW patients (p = .0086); however, a significant difference was not shown in patients who received TAM and OFS (p = .0921). CONCLUSION: High BMI was associated with worse prognosis in premenopausal patients with HR-positive BC who received adjuvant TAM. The role of OFS as adjuvant endocrine therapy remains unclear, and further studies are required to explore the adequate management of obese premenopausal patients.

Transcriptomic intratumor heterogeneity of breast cancer patient-derived organoids may reflect the unique biological features of the tumor of origin.

BACKGROUND: The intratumor heterogeneity (ITH) of cancer cells plays an important role in breast cancer resistance and recurrence. To develop better therapeutic strategies, it is necessary to understand the molecular mechanisms underlying ITH and their functional significance. Patient-derived organoids (PDOs) have recently been utilized in cancer research. They can also be used to study ITH as cancer cell diversity is thought to be maintained within the organoid line. However, no reports investigated intratumor transcriptomic heterogeneity in organoids derived from patients with breast cancer. This study aimed to investigate transcriptomic ITH in breast cancer PDOs. METHODS: We established PDO lines from ten patients with breast cancer and performed single-cell transcriptomic analysis. First, we clustered cancer cells for each PDO using the Seurat package. Then, we defined and compared the cluster-specific gene signature (ClustGS) corresponding to each cell cluster in each PDO. RESULTS: Cancer cells were clustered into 3-6 cell populations with distinct cellular states in each PDO line. We identified 38 clusters with ClustGS in 10 PDO lines and used Jaccard similarity index to compare the similarity of these signatures. We found that 29 signatures could be categorized into 7 shared meta-ClustGSs, such as those related to the cell cycle or epithelial-mesenchymal transition, and 9 signatures were unique to single PDO lines. These unique cell populations appeared to represent the characteristics of the original tumors derived from patients. CONCLUSIONS: We confirmed the existence of transcriptomic ITH in breast cancer PDOs. Some cellular states were commonly observed in multiple PDOs, whereas others were specific to single PDO lines. The combination of these shared and unique cellular states formed the ITH of each PDO.

Retrospective study on the effectiveness of medroxyprogesterone acetate in the treatment of ER-positive/HER2-negative post-menopausal advanced breast cancer: an additional analysis of the JBCRG-C06 Safari study.

BACKGROUND: Only old evidence exists to back up the use of medroxyprogesterone acetate. Therefore, this study aimed to explore the factors that influence the time to treatment failure of medroxyprogesterone acetate in real-world settings as late-line treatment. METHODS: This was a cohort study that used the database of the Safari study on oestrogen receptor-positive post-menopausal advanced breast cancer (UMIN000015168). We created Kaplan-Meier curves for time to treatment failure with medroxyprogesterone acetate. Further, univariate and multivariate analyses were performed using a Cox hazard model of the clinicopathological factors involved in the time to treatment failure of medroxyprogesterone acetate. RESULTS: From the 1031 patients in the Safari study, 279 patients were selected as the population for the analysis of effectiveness of medroxyprogesterone acetate monotherapy. In the analysis of medroxyprogesterone acetate by treatment line, the median time to treatment failure was 3.0 months for third-line treatment and 4.1 months for fourth and subsequent treatment lines. In cases where medroxyprogesterone acetate was used as a third-line or later endocrine treatment, multivariate analysis showed that the length of the disease-free interval was correlated with the length of time to treatment failure of medroxyprogesterone acetate (P = 0.004). With medroxyprogesterone acetate monotherapy as the fourth-line or later treatment, 20% of the patients achieved a time to treatment failure of 12 months or longer. CONCLUSION: In actual clinical practice, patients treated with medroxyprogesterone acetate alone as the fourth or subsequent treatment lines showed a time to treatment failure of 4 months, suggesting that there is merit in using medroxyprogesterone acetate even in late treatment lines, especially in patients with long disease-free interval and those who are difficult to treat using other antineoplastic agents.